Airport weather · KORD

ORD Airport Weather by Month

Weather at Chicago O'Hare International Airport, 2000 to 2025: flight categories, fog, storms and runway crosswinds from the airport's own hourly reports.

Compiled by PilotPassionReviewed by Keith M.
Updated October 20, 2026Cited 3 sources
A regional jet at a gate at Chicago O'Hare International Airport with United Airlines aircraft parked beyond it
Aircraft at the gates at Chicago O'Hare International Airport (photographed in 2018) Photo: Raysonho @ Open Grid Scheduler / Scalable Grid Engine, CC0. Source

VFR hours

77.6%

15.2% marginal VFR; 7.2% IFR or worse

Highest IFR-or-worse share

January

15.4% of hours

Lowest IFR-or-worse share

July

1.9% of hours

Fog, average year

38 hours

0.45% of hourly reports

Thunderstorms, average year

59 hours

Storms reported at the airport

Crosswind coverage at 13 kt

96.9%

At least one runway axis at or below this component

Precipitation, average year

37.9 in

126 wet days

On this page
  1. 01ORD weather, month by month
  2. 02Flight categories at ORD
  3. 03Weather by time of day
  4. 04Fog
  5. 05Thunderstorms, precipitation and snow
  6. 06Wind and runway crosswinds
  7. 07Temperature, humidity and daylight
  8. 08Check a date
  9. 09Year to year
  10. 10ORD, PWK, MDW compared
  11. 11Best and worst months by hazard
  12. 12Records and extremes
  13. 13Planning with ORD climate records
  14. 14Questions about ORD weather
  15. 15Sources and method

ORD reports VFR in 77.6% of hours and IFR or worse in 7.2%. The IFR-or-worse category means a ceiling below 1,000 feet or visibility below 3 statute miles.

January has the highest share of IFR-or-worse hours, at 15.4%. July has the lowest, at 1.9%.

This page uses 222,224 hourly reports from 2000 to 2025, covering 97.50% of hours in the period. Daily temperature and precipitation come from GHCN-Daily station USW00094846.

01

ORD weather, month by month

Pick a month to see the data.

January

15.4% of hours at IFR or worse.

January ranks 1 of 12 for the share of hours at IFR or worse, from highest to lowest: 15.4%. VFR accounts for 60.6%.

The highest IFR-or-worse share is 8 am to 9 am (18.7%); the lowest is 6 pm to 7 pm (12.3%). Times are local.

Average daily highs are 32°F and lows 18°F. Precipitation averages 1.9 in across 11.2 wet days.

Fog appears in 1.09% of hours; thunderstorms at the airport in 0.06%; wind or gusts of 25 kt or more in 4.7%.

Snowfall averages 11.8 in in this month.

VFR hours
60.6%
IFR or worse
15.4%
High / low
32°F / 18°F
Daylight
9.4 h
Precipitation
1.9 in
Snowfall
11.8 in
Fog hours
1.09%
25 kt+ wind
4.7%

February

11.5% of hours at IFR or worse.

February ranks 3 of 12 for the share of hours at IFR or worse, from highest to lowest: 11.5%. VFR accounts for 67.1%.

The highest IFR-or-worse share is 8 am to 9 am (14.8%); the lowest is 2 pm to 3 pm (9.3%). Times are local.

Average daily highs are 36°F and lows 20°F. Precipitation averages 2.0 in across 9.3 wet days.

Fog appears in 0.91% of hours; thunderstorms at the airport in 0.10%; wind or gusts of 25 kt or more in 6.4%.

Snowfall averages 10.9 in in this month.

VFR hours
67.1%
IFR or worse
11.5%
High / low
36°F / 20°F
Daylight
10.6 h
Precipitation
2.0 in
Snowfall
10.9 in
Fog hours
0.91%
25 kt+ wind
6.4%

March

8.7% of hours at IFR or worse.

March ranks 4 of 12 for the share of hours at IFR or worse, from highest to lowest: 8.7%. VFR accounts for 72.8%.

The highest IFR-or-worse share is 6 am to 7 am (12.8%); the lowest is 7 pm to 8 pm (5.4%). Times are local.

Average daily highs are 48°F and lows 31°F. Precipitation averages 2.6 in across 11.1 wet days.

Fog appears in 0.72% of hours; thunderstorms at the airport in 0.33%; wind or gusts of 25 kt or more in 7.5%.

Snowfall averages 4.1 in in this month.

VFR hours
72.8%
IFR or worse
8.7%
High / low
48°F / 31°F
Daylight
11.9 h
Precipitation
2.6 in
Snowfall
4.1 in
Fog hours
0.72%
25 kt+ wind
7.5%

April

7.8% of hours at IFR or worse.

April ranks 5 of 12 for the share of hours at IFR or worse, from highest to lowest: 7.8%. VFR accounts for 79.9%.

The highest IFR-or-worse share is 5 am to 6 am (10.4%); the lowest is 1 pm to 2 pm (5.7%). Times are local.

Average daily highs are 60°F and lows 40°F. Precipitation averages 3.6 in across 11.8 wet days.

Fog appears in 0.20% of hours; thunderstorms at the airport in 0.73%; wind or gusts of 25 kt or more in 8.8%.

Snowfall averages 1.2 in in this month.

VFR hours
79.9%
IFR or worse
7.8%
High / low
60°F / 40°F
Daylight
13.3 h
Precipitation
3.6 in
Snowfall
1.2 in
Fog hours
0.20%
25 kt+ wind
8.8%

May

6.0% of hours at IFR or worse.

May ranks 7 of 12 for the share of hours at IFR or worse, from highest to lowest: 6.0%. VFR accounts for 83.2%.

The highest IFR-or-worse share is 7 am to 8 am (9.8%); the lowest is 6 pm to 7 pm (3.1%). Times are local.

Average daily highs are 70°F and lows 50°F. Precipitation averages 4.5 in across 12.5 wet days.

Fog appears in 0.28% of hours; thunderstorms at the airport in 1.27%; wind or gusts of 25 kt or more in 4.7%.

Snowfall averages 0.0 in in this month.

VFR hours
83.2%
IFR or worse
6.0%
High / low
70°F / 50°F
Daylight
14.5 h
Precipitation
4.5 in
Snowfall
None to trace
Fog hours
0.28%
25 kt+ wind
4.7%

June

4.8% of hours at IFR or worse.

June ranks 8 of 12 for the share of hours at IFR or worse, from highest to lowest: 4.8%. VFR accounts for 86.5%.

The highest IFR-or-worse share is 6 am to 7 am (9.1%); the lowest is 4 pm to 5 pm (1.7%). Times are local.

Average daily highs are 81°F and lows 61°F. Precipitation averages 4.1 in across 11.5 wet days.

Fog appears in 0.20% of hours; thunderstorms at the airport in 1.51%; wind or gusts of 25 kt or more in 2.7%.

Snowfall averages 0.0 in in this month.

VFR hours
86.5%
IFR or worse
4.8%
High / low
81°F / 61°F
Daylight
15.2 h
Precipitation
4.1 in
Snowfall
None to trace
Fog hours
0.20%
25 kt+ wind
2.7%

July

1.9% of hours at IFR or worse.

July ranks 12 of 12 for the share of hours at IFR or worse, from highest to lowest: 1.9%. VFR accounts for 91.1%.

The highest IFR-or-worse share is 5 am to 6 am (5.2%); the lowest is 1 pm to 2 pm (0.1%). Times are local.

Average daily highs are 84°F and lows 66°F. Precipitation averages 4.2 in across 10.3 wet days.

Fog appears in 0.03% of hours; thunderstorms at the airport in 1.60%; wind or gusts of 25 kt or more in 1.0%.

Snowfall averages 0.0 in in this month.

VFR hours
91.1%
IFR or worse
1.9%
High / low
84°F / 66°F
Daylight
15.0 h
Precipitation
4.2 in
Snowfall
None to trace
Fog hours
0.03%
25 kt+ wind
1.0%

August

2.0% of hours at IFR or worse.

August ranks 11 of 12 for the share of hours at IFR or worse, from highest to lowest: 2.0%. VFR accounts for 89.5%.

The highest IFR-or-worse share is 6 am to 7 am (5.5%); the lowest is 1 pm to 2 pm (0.2%). Times are local.

Average daily highs are 83°F and lows 65°F. Precipitation averages 4.2 in across 9.2 wet days.

Fog appears in 0.07% of hours; thunderstorms at the airport in 1.37%; wind or gusts of 25 kt or more in 0.9%.

Snowfall averages 0.0 in in this month.

VFR hours
89.5%
IFR or worse
2.0%
High / low
83°F / 65°F
Daylight
13.9 h
Precipitation
4.2 in
Snowfall
None to trace
Fog hours
0.07%
25 kt+ wind
0.9%

September

3.0% of hours at IFR or worse.

September ranks 10 of 12 for the share of hours at IFR or worse, from highest to lowest: 3.0%. VFR accounts for 86.9%.

The highest IFR-or-worse share is 7 am to 8 am (7.3%); the lowest is 3 pm to 4 pm (1.2%). Times are local.

Average daily highs are 76°F and lows 57°F. Precipitation averages 3.1 in across 8.4 wet days.

Fog appears in 0.20% of hours; thunderstorms at the airport in 0.65%; wind or gusts of 25 kt or more in 1.8%.

Snowfall averages 0.0 in in this month.

VFR hours
86.9%
IFR or worse
3.0%
High / low
76°F / 57°F
Daylight
12.6 h
Precipitation
3.1 in
Snowfall
None to trace
Fog hours
0.20%
25 kt+ wind
1.8%

October

4.7% of hours at IFR or worse.

October ranks 9 of 12 for the share of hours at IFR or worse, from highest to lowest: 4.7%. VFR accounts for 81.0%.

The highest IFR-or-worse share is 5 am to 6 am (8.2%); the lowest is 5 pm to 6 pm (2.5%). Times are local.

Average daily highs are 63°F and lows 45°F. Precipitation averages 3.3 in across 10.9 wet days.

Fog appears in 0.15% of hours; thunderstorms at the airport in 0.40%; wind or gusts of 25 kt or more in 5.0%.

Snowfall averages 0.2 in in this month.

VFR hours
81.0%
IFR or worse
4.7%
High / low
63°F / 45°F
Daylight
11.2 h
Precipitation
3.3 in
Snowfall
0.2 in
Fog hours
0.15%
25 kt+ wind
5.0%

November

7.0% of hours at IFR or worse.

November ranks 6 of 12 for the share of hours at IFR or worse, from highest to lowest: 7.0%. VFR accounts for 73.2%.

The highest IFR-or-worse share is 7 am to 8 am (10.3%); the lowest is 5 pm to 6 pm (4.2%). Times are local.

Average daily highs are 49°F and lows 34°F. Precipitation averages 2.2 in across 9.3 wet days.

Fog appears in 0.43% of hours; thunderstorms at the airport in 0.13%; wind or gusts of 25 kt or more in 6.3%.

Snowfall averages 2.4 in in this month.

VFR hours
73.2%
IFR or worse
7.0%
High / low
49°F / 34°F
Daylight
9.9 h
Precipitation
2.2 in
Snowfall
2.4 in
Fog hours
0.43%
25 kt+ wind
6.3%

December

14.3% of hours at IFR or worse.

December ranks 2 of 12 for the share of hours at IFR or worse, from highest to lowest: 14.3%. VFR accounts for 59.1%.

The highest IFR-or-worse share is 7 am to 8 am (18.3%); the lowest is 9 pm to 10 pm (12.0%). Times are local.

Average daily highs are 37°F and lows 23°F. Precipitation averages 2.3 in across 11.0 wet days.

Fog appears in 1.12% of hours; thunderstorms at the airport in 0.07%; wind or gusts of 25 kt or more in 5.5%.

Snowfall averages 7.9 in in this month.

VFR hours
59.1%
IFR or worse
14.3%
High / low
37°F / 23°F
Daylight
9.1 h
Precipitation
2.3 in
Snowfall
7.9 in
Fog hours
1.12%
25 kt+ wind
5.5%

02

Flight categories at ORD

Pilots sort every weather report into four flight categories using the lowest cloud ceiling and the visibility. The chart shows how many hours each month fall short of VFR, split by how far short.

January has the highest share of IFR-or-worse hours. For LIFR alone, the highest share is in January; for MVFR it is in December.

Share of hours below VFR, by month

Percent of all hourly reports in each month that fell short of VFR.

0204060%39.5Jan32.9Feb27.2Mar20.1Apr16.9May13.4Jun8.9Jul10.4Aug13.2Sep18.9Oct26.8Nov40.9Dec
0204060%Jan39.5Feb32.9Mar27.2Apr20.1May16.9Jun13.4Jul8.9Aug10.4Sep13.2Oct18.9Nov26.8Dec40.9
  • LIFR
  • IFR
  • MVFR
View the numbers
Share of hours by flight category and month, ORD
MonthVFRMVFRIFRLIFRIFR or worse
January60.6%24.1%10.7%4.7%15.4%
February67.1%21.4%7.9%3.6%11.5%
March72.8%18.5%6.1%2.6%8.7%
April79.9%12.3%5.9%1.9%7.8%
May83.2%10.9%4.1%1.9%6.0%
June86.5%8.6%3.3%1.5%4.8%
July91.1%7.0%1.6%0.3%1.9%
August89.5%8.4%1.7%0.3%2.0%
September86.9%10.2%2.5%0.5%3.0%
October81.0%14.2%4.1%0.6%4.7%
November73.2%19.8%5.3%1.7%7.0%
December59.1%26.6%10.3%4.0%14.3%

The rest of each month is VFR. Hover or tap a bar for the full split.

Source: NOAA/NWS airport observations via Iowa Environmental Mesonet
VFR
Ceiling above 3,000 feet and visibility above 5 miles.
MVFR
Marginal VFR. Ceiling of 1,000 to 3,000 feet, or visibility of 3 to 5 miles.
IFR
Ceiling of 500 to under 1,000 feet, or visibility of 1 to under 3 miles.
LIFR
Ceiling under 500 feet, or visibility under 1 mile.

A ceiling counts only broken or overcast layers, or vertical visibility into fog or heavy precipitation. A few scattered clouds do not count.

Sky cover by month

Share of hours by the highest cloud cover reported.

0255075100%JanFebMarAprMayJunJulAugSepOctNovDec
0255075100%Jan100.0Feb100.0Mar100.0Apr99.9May100.0Jun100.0Jul100.1Aug100.1Sep100.0Oct100.0Nov100.1Dec100.0
  • Clear or few
  • Scattered
  • Broken
  • Overcast
View the numbers
Sky cover by month
MonthClear or fewScatteredBrokenOvercast
January25%7%16%52%
February29%8%18%45%
March25%10%23%43%
April26%10%25%39%
May23%14%31%32%
June28%17%32%23%
July29%21%34%16%
August32%20%31%17%
September38%16%26%20%
October31%11%24%34%
November27%9%21%43%
December22%7%18%54%
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

03

Weather by time of day

Each square is one month and one hour of the day (local time) and shows the share of hours that hit the condition you pick. The stronger the colour, the more likely.

Within January, the highest IFR-or-worse rate occurs 8 am to 9 am. The lowest occurs 6 pm to 7 pm.

Condition by month and hour of day

Local time. Pick a condition to repaint the grid.

12a3a6a9a12p3p6p9pJanFebMarAprMayJunJulAugSepOctNovDec
JFMAMJJASOND12a3a6a9a12p3p6p9p

Ceiling under 1,000 feet or visibility under 3 miles. Peak square: January, 8 am, 18.7% of hours.

Each square is one month and one hour, averaged over all years.

Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

04

Fog

0.45% of hours report fog, about 38 hours per year.

Fog has its highest monthly share in December and its lowest in July. Across all months, it is most frequent 6 am to 7 am.

The longest sequence of hourly fog reports lasts 19 hours. This counts routine reports, so short events between reports can be missed.

Share of hours with fog, by month

Fog reported by the station.

0.00.51.01.5%JanFebMarAprMayJun0.03JulAugSepOctNov1.12Dec
0.00.51.01.5%Jan1.09Feb0.91Mar0.72Apr0.20May0.28Jun0.20Jul0.03Aug0.07Sep0.20Oct0.15Nov0.43Dec1.12
View the numbers
Share of hours with fog, by month
MonthValue (%)
January1.09
February0.91
March0.72
April0.20
May0.28
June0.20
July0.03
August0.07
September0.20
October0.15
November0.43
December1.12
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Fog by hour of day

All months combined, local time.

0.00.51.01.5%1.06%12a3a6a9a12p3p6p9p
0.00.51.01.5%1.06%12a3a6a9a12p3p6p9p
View the numbers
Share of hours with fog by hour of day
HourFog
12 am0.52%
1 am0.47%
2 am0.50%
3 am0.46%
4 am0.65%
5 am0.76%
6 am1.06%
7 am0.79%
8 am0.51%
9 am0.39%
10 am0.26%
11 am0.35%
12 pm0.27%
1 pm0.41%
2 pm0.33%
3 pm0.42%
4 pm0.37%
5 pm0.25%
6 pm0.24%
7 pm0.35%
8 pm0.31%
9 pm0.31%
10 pm0.38%
11 pm0.38%
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

05

Thunderstorms, precipitation and snow

Present-weather codes count thunderstorms at the airport.

July has the highest monthly thunderstorm rate, at 1.60% of hours.

May has the highest average precipitation total; January has the lowest. The annual average is 37.9 in.

The largest daily precipitation total in the downloaded station record is 6.86 in, on July 23, 2011.

January has the highest average snowfall total. Annual snowfall averages 38.5 in.

Share of hours with a thunderstorm at the airport

By month.

0.00.51.01.52.0%0.06JanFebMarAprMayJun1.60JulAugSepOctNovDec
0.00.51.01.52.0%Jan0.06Feb0.10Mar0.33Apr0.73May1.27Jun1.51Jul1.60Aug1.37Sep0.65Oct0.40Nov0.13Dec0.07
View the numbers
Share of hours with a thunderstorm at the airport
MonthValue (%)
January0.06
February0.10
March0.33
April0.73
May1.27
June1.51
July1.60
August1.37
September0.65
October0.40
November0.13
December0.07
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Average precipitation by month

Inches of rain and melted snow.

012345 in1.9JanFebMarApr4.5MayJunJulAugSepOctNovDec
012345 inJan1.9Feb2.0Mar2.6Apr3.6May4.5Jun4.1Jul4.2Aug4.2Sep3.1Oct3.3Nov2.2Dec2.3
View the numbers
Average precipitation by month
MonthValue ( in)
January1.9
February2.0
March2.6
April3.6
May4.5
June4.1
July4.2
August4.2
September3.1
October3.3
November2.2
December2.3
Source: NOAA GHCN-Daily

Average snowfall by month

Inches of snowfall depth, average over the years.

03581013 in11.8JanFebMarApr0.0MayJunJulAugSepOctNovDec
03581013 inJan11.8Feb10.9Mar4.1Apr1.2May0.0Jun0.0Jul0.0Aug0.0Sep0.0Oct0.2Nov2.4Dec7.9
View the numbers
Average snowfall by month
MonthValue ( in)
January11.8
February10.9
March4.1
April1.2
May0.0
June0.0
July0.0
August0.0
September0.0
October0.2
November2.4
December7.9
Source: NOAA GHCN-Daily

06

Wind and runway crosswinds

Runway axes and true headings come from OurAirports.

The most frequent wind sector is W, among reports with sustained wind of at least 3 kt.

Using the better aligned runway axis, the crosswind component stays at or below 13 kt in 96.9% of hours with a wind-speed report.

The share with wind or gusts of at least 25 kt is highest in April and lowest in August. Crosswind above 15 kt on every available axis is most frequent in April.

The largest sustained wind or reported gust in these hourly observations is 70 kt.

Where the wind comes from

Share of hours by direction the wind blows from and speed. Lines mark the runway axes.

5%10%15%042209/1027/28NESW
  • 3 to 9 kt
  • 10 to 17
  • 18 to 24
  • 25 or more
  • Runway axes

Speed uses the stronger of sustained wind and gust. Calm hours (under 3 kt) are left out of the rose.

Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

ORD runways and crosswind exposure

Drawn to scale, north up. A stronger colour means crosswind above 15 kt in more hours.

1 mileN04L22R04R22L09C27C09L27R09R27L10C28C10L28R10R28L
View the numbers
Crosswind exposure by runway axis
Runway axisOver 15 ktOver 20 kt
04/226.6% of hours2.7% of hours
09/278.5% of hours3.7% of hours
10/288.5% of hours3.7% of hours

Runway positions from OurAirports. Terminals and taxiways are not shown.

Source: OurAirports runway data; NOAA/NWS airport observations via Iowa Environmental Mesonet

Share of hours with wind or gusts of 25 kt or more

By month.

0246810%JanFebMar8.8AprMayJunJul0.9AugSepOctNovDec
0246810%Jan4.7Feb6.4Mar7.5Apr8.8May4.7Jun2.7Jul1.0Aug0.9Sep1.8Oct5.0Nov6.3Dec5.5
View the numbers
Share of hours with wind or gusts of 25 kt or more
MonthValue (%)
January4.7
February6.4
March7.5
April8.8
May4.7
June2.7
July1.0
August0.9
September1.8
October5.0
November6.3
December5.5
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Hours when even the best runway has over 15 kt of crosswind

Share of hours, by month.

01234%JanFebMar3.62AprMayJunJul0.62AugSepOctNovDec
01234%Jan2.15Feb2.74Mar3.06Apr3.62May1.85Jun1.25Jul0.63Aug0.62Sep1.21Oct2.46Nov3.52Dec2.45
View the numbers
Hours when even the best runway has over 15 kt of crosswind
MonthValue (%)
January2.15
February2.74
March3.06
April3.62
May1.85
June1.25
July0.63
August0.62
September1.21
October2.46
November3.52
December2.45
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Which runway end the wind favours

Each hour is assigned to the numbered runway end with the largest headwind component. Parallel ends with the same heading are grouped. Ties go to the first sorted axis. This is not a record of runway use.

0255075100%JanFebMarAprMayJunJulAugSepOctNovDec
0255075100%Jan99.9Feb99.9Mar100.0Apr99.9May100.0Jun100.1Jul100.1Aug99.9Sep100.0Oct100.1Nov100.0Dec100.0
  • 10
  • 22
  • 27
  • 28
  • 04
  • 09
  • calm
View the numbers
Wind-only runway preference
Month102227280409calm
January0.0%30.6%42.3%0.0%14.8%7.8%4.4%
February0.0%27.9%37.8%0.0%18.8%10.6%4.8%
March0.0%24.7%26.1%0.0%27.5%15.5%6.2%
April0.0%24.2%22.5%0.0%28.8%18.4%6.0%
May0.0%26.2%17.5%0.0%30.1%19.0%7.2%
June0.0%30.9%20.1%0.0%24.3%15.1%9.7%
July0.0%27.7%23.6%0.0%23.9%13.3%11.6%
August0.0%29.1%19.9%0.0%23.9%14.3%12.7%
September0.0%30.0%18.9%0.0%23.3%16.0%11.8%
October0.0%32.5%27.7%0.0%18.2%13.5%8.2%
November0.0%38.6%32.5%0.0%14.1%9.0%5.8%
December0.0%33.0%37.4%0.0%13.5%10.8%5.3%
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

07

Temperature, humidity and daylight

Daily temperature comes from GHCN-Daily.

July has the highest average daily high; January has the lowest.

Dew points of at least 70°F are most frequent in July.

Mid-month daylight is longest in June and shortest in December. Sunrise and sunset use the configured US daylight saving rule.

Average high and low by month

Lines are the average. Shaded bands cover the middle 80% of days.

0°20°40°60°80°100°32°FHighLowJanFebMarAprMayJunJulAugSepOctNovDec
0°20°40°60°80°100°32°FHighLowJFMAMJJASOND
  • Daily high
  • Daily low
View the numbers
Temperature by month at ORD
MonthAverage highAverage lowDays 90F+Nights 32F or colderRecord highRecord low
January32°F18°F0.027.865°F (1989)-27°F (1985)
February36°F20°F0.024.874°F (2024)-19°F (1996)
March48°F31°F0.018.088°F (1986)-8°F (1962)
April60°F40°F0.05.391°F (1980)7°F (1982)
May70°F50°F0.60.297°F (2012)24°F (1966)
June81°F61°F3.80.0104°F (1988)36°F (1963)
July84°F66°F5.00.0104°F (1995)40°F (1965)
August83°F65°F3.30.0101°F (1991)41°F (1964)
September76°F57°F1.20.099°F (1960)28°F (1974)
October63°F45°F0.01.991°F (1963)17°F (1981)
November49°F34°F0.013.578°F (1978)1°F (1958)
December37°F23°F0.024.671°F (1982)-25°F (1983)

Dashed line marks freezing.

Source: NOAA GHCN-Daily

Share of hours with a dew point of 70F or higher

By month.

05101520%0.0JanFebMarAprMayJun15.6JulAugSepOctNovDec
05101520%Jan0.0Feb0.0Mar0.0Apr0.0May0.3Jun5.7Jul15.6Aug13.3Sep2.7Oct0.1Nov0.0Dec0.0
View the numbers
Share of hours with a dew point of 70F or higher
MonthValue (%)
January0.0
February0.0
March0.0
April0.0
May0.3
June5.7
July15.6
August13.3
September2.7
October0.1
November0.0
December0.0
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Sunrise and sunset

Local clock time. The shaded band is daylight; the small steps are the clocks changing.

4 am6 am8 am10 am12 pm2 pm4 pm6 pm8 pmJanFebMarAprMayJunJulAugSepOctNovDecLatest sunrise 7:26 amEarliest 5:15 am
4 am8 am12 pm4 pm8 pmJFMAMJJASOND
View the numbers
Sunrise, sunset and daylight, mid-month
MonthSunriseSunsetDaylight
January7:17 am4:43 pm9.4 hours
February6:49 am5:23 pm10.6 hours
March7:06 am6:57 pm11.9 hours
April6:13 am7:31 pm13.3 hours
May5:32 am8:03 pm14.5 hours
June5:15 am8:28 pm15.2 hours
July5:28 am8:26 pm15.0 hours
August5:59 am7:54 pm13.9 hours
September6:30 am7:04 pm12.6 hours
October7:03 am6:12 pm11.2 hours
November6:41 am4:32 pm9.9 hours
December7:12 am4:21 pm9.1 hours
Source: calculated by PilotPassion from the airport's position

08

Check a date

Use a seven-day window on each side of your date across 26 years.

October 15 at ORD

Chance of low cloud or poor visibility (IFR or worse)

  • Overnight12 am to 6 am4.5%
  • Morning6 am to noon4.4%
  • Afternoonnoon to 6 pm2.2%
  • Evening6 pm to midnight1.9%

The day

Typical high
64°F
Typical low
45°F
Sunrise
7:04 am
Sunset
6:10 pm
Measurable precipitation
33% of days
Snow of 0.1 in or more
0% of days
Wind or gusts 25 kt+
4.5% of hours

These historical frequencies are not a forecast.

09

Year to year

Each bar summarizes one local calendar year.

IFR-or-worse hours by year

Local calendar years.

0246810%9.12000200220042006200820104.92012201420162018202020222024average 7.2
0246810%'009.1'01'02'03'04'05'06'07'08'09'10'11'124.9'13'14'15'16'17'18'19'20'21'22'23'24'25
View the numbers
IFR-or-worse hours by year
YearShare of hours
20009.1%
20017.1%
20026.0%
20037.5%
20046.2%
20056.7%
20067.2%
20077.6%
20088.5%
20097.7%
20107.5%
20117.4%
20124.9%
20137.2%
20147.2%
20158.9%
20167.0%
20177.3%
20189.1%
20198.6%
20207.5%
20216.2%
20225.7%
20237.6%
20247.1%
20255.1%
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet

Precipitation by year

Local calendar years.

0204060 in20002002200424.1200650.9200820102012201420162018202020222024average 37.9
0204060 in'00'01'02'03'04'0524.1'06'07'0850.9'09'10'11'12'13'14'15'16'17'18'19'20'21'22'23'24'25
View the numbers
Precipitation by year
YearInches
200033.4 in
200145.8 in
200234.0 in
200332.0 in
200431.6 in
200524.1 in
200642.0 in
200735.8 in
200850.9 in
200942.6 in
201037.6 in
201149.9 in
201226.9 in
201342.1 in
201439.5 in
201539.9 in
201636.0 in
201743.1 in
201849.3 in
201949.6 in
202039.2 in
202130.2 in
202232.0 in
202333.8 in
202435.0 in
202529.8 in
Source: NOAA GHCN-Daily

Snowfall by year

Local calendar years.

020406080 in200010.020022004200620082010201270.0201420162018202020222024average 38.5
020406080 in'00'0110.0'02'03'04'05'06'07'08'09'10'11'12'13'1470.0'15'16'17'18'19'20'21'22'23'24'25
View the numbers
Snowfall by year
YearInches
200057.9 in
200110.0 in
200242.3 in
200317.5 in
200429.1 in
200546.1 in
200620.2 in
200747.1 in
200865.2 in
200951.0 in
201049.7 in
201143.5 in
201219.1 in
201344.5 in
201470.0 in
201563.5 in
201633.3 in
201713.9 in
201844.8 in
201945.9 in
202028.0 in
202147.2 in
202235.4 in
202319.8 in
202423.6 in
202532.4 in
Source: NOAA GHCN-Daily

10

ORD, PWK, MDW compared

The same hourly method and period apply to each station.

ORD's VFR share is higher than PWK's: 77.6% versus 76.2%.

ORD's VFR share is lower than MDW's: 77.6% versus 77.8%.

IFR-or-worse hours by month and airport

Same method and period for each station.

05101520%ORDPWKMDWJanFebMarAprMayJunJulAugSepOctNovDec
05101520%JFMAMJJASOND
  • ORD
  • PWK
  • MDW
Source: NOAA/NWS airport observations via Iowa Environmental Mesonet
Airport comparison
MeasureORDPWKMDW
VFR hours77.6%76.2%77.8%
IFR or worse hours7.2%8.6%6.9%
Fog hours0.45%0.49%0.30%
Fog hours per year384126
Thunderstorm hours per year592859
Wind or gusts 25 kt+4.6%3.2%4.9%
Crosswind coverage at 13 kt96.9%92.9%96.2%

11

Best and worst months by hazard

Each row is a different weather problem. A stronger colour means a higher rate that month, and the three worst months for each hazard have the strongest colour.

Hazard calendar

The strongest-coloured cells are the three worst months for that row. A pale cell with a 0 means none at all.

JanFebMarAprMayJunJulAugSepOctNovDecLow cloud (IFR or worse)151298652235714Fog1.10.90.70.20.30.2<0.10.10.20.20.41.1Thunderstorm at the airport0.10.10.30.71.31.51.61.40.70.40.10.1Snow13.611.95.51.80.0<0.10.0<0.10.00.23.59.3Freezing rain or icepellets1.00.50.20.10.00.00.00.00.0<0.10.10.7Wind or gusts 25 kt+568953112565Crosswind over 15 kt (allrunways)2.22.73.13.61.91.30.60.61.22.53.52.5Heat (days of 90F orhotter)0.00.00.00.00.63.85.03.31.20.00.00.0Frost (nights of 32F orcolder)2825185<1000021425Humid (dew point 70F+)0000<1616133<100
CloudFogStormSnowIceWindXwindHeatFrostHumidJan151.10.113.61.052.20.0280Feb120.90.111.90.562.70.0250Mar90.70.35.50.283.10.0180Apr80.20.71.80.193.60.050May60.31.30.00.051.90.6<1<1Jun50.21.5<0.10.031.33.806Jul2<0.11.60.00.010.65.0016Aug20.11.4<0.10.010.63.3013Sep30.20.70.00.021.21.203Oct50.20.40.2<0.152.50.02<1Nov70.40.13.50.163.50.0140Dec141.10.19.30.752.50.0250
View the numbers
Hazard rates by month
HazardJanFebMarAprMayJunJulAugSepOctNovDec
Low cloud (IFR or worse)151298652235714
Fog1.10.90.70.20.30.2<0.10.10.20.20.41.1
Thunderstorm at the airport0.10.10.30.71.31.51.61.40.70.40.10.1
Snow13.611.95.51.80.0<0.10.0<0.10.00.23.59.3
Freezing rain or ice pellets1.00.50.20.10.00.00.00.00.0<0.10.10.7
Wind or gusts 25 kt+568953112565
Crosswind over 15 kt (all runways)2.22.73.13.61.91.30.60.61.22.53.52.5
Heat (days of 90F or hotter)0.00.00.00.00.63.85.03.31.20.00.00.0
Frost (nights of 32F or colder)2825185<1000021425
Humid (dew point 70F+)0000<1616133<100

Weather-code, wind and humidity values are percentages of hourly reports. Heat and frost are days in an average year. A value shown as <0.1 or <1 is above zero but under that figure.

Source: NOAA/NWS airport observations via Iowa Environmental Mesonet; NOAA GHCN-Daily

12

Records and extremes

  • Hottest daily high104°FJune 20, 1988
  • Coldest daily low-27°FJanuary 20, 1985
  • Largest daily precipitation6.9 inJuly 23, 2011
  • Largest daily snowfall18.6 inJanuary 2, 1999

Daily records cover the downloaded station history, starting 1946-10-09; hourly summaries cover 2000 to 2025.

13

Planning with ORD climate records

For travelers

  • July has the lowest historical IFR-or-worse rate. A monthly average does not predict weather on a particular trip.

For pilots

  • Use the charts to compare historical conditions. Get current METARs, TAFs and an official briefing before flying.

This page is for general information and trip planning. It is not an aviation weather briefing and must not be used for flight planning. Always get current weather from an official source such as aviationweather.gov or 1-800-WX-BRIEF before flying.

14

Questions about ORD weather

Which month has the most IFR-or-worse hours at ORD?

January has the highest share, at 15.4%. July has the lowest, at 1.9%.

When is fog most frequent at ORD?

December has the highest monthly share of fog reports. The annual share is 0.45%.

When are thunderstorms most frequent at ORD?

July has the highest share of hours with thunderstorms reported at the airport.

How much snowfall does ORD record?

Annual snowfall averages 38.5 in; January has the highest monthly average.

Is this a forecast?

No. The hourly summaries cover 2000 to 2025. Use current reports and forecasts for KORD from aviationweather.gov.

15

Sources and method

Sources

Hourly weather
Iowa Environmental Mesonet archive of US National Weather Service routine hourly observations, report type 3, requested in UTC and filtered to local years 2000 to 2025.
Daily climate
NOAA NCEI GHCN-Daily station USW00094846. Menne et al. (2012), Global Historical Climatology Network Daily, doi:10.7289/V5D21VHZ.
Runways
OurAirports public domain runway data: source repository. Headings are degrees true. The first listed runway represents each numbered axis in crosswind calculations.
Time and daylight
Standard UTC offset -6 hours; US daylight saving rule, including the earlier rule before its statutory change. Solar times use the airport coordinates and NOAA equations.

Definitions

Sampling
One routine report per local clock hour. The first report is retained when hours repeat, including the autumn clock change.
Weather codes
Fog and thunderstorms exclude vicinity codes.
Wind
The stronger of sustained wind and gust is used for crosswind. Calm and variable direction count as zero crosswind.
Daily averages
Monthly totals and day counts are divided by the number of years in the analysis period.

Limits

  • Routine hourly sampling misses events between observations.
  • Wind above 100 kt, temperature outside -30 to 115 F and dew point outside -40 to 90 F are discarded as sensor glitches.
  • Wind-only runway preferences do not describe ATC assignments.

Weather data comes from the US National Weather Service and NOAA via IEM. PilotPassion is not affiliated with or endorsed by these agencies.

Travelers walking down Concourse H in Terminal 3 at Chicago O'Hare under a glass-panelled ceiling
Concourse H in Terminal 3 at Chicago O'Hare International Airport Photo: Mattpopovich, CC0. Source

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