Chicago, IL weather in August
Expect warm, often humid weather with some rain in Chicago in August, with highs near 83°F and lows near 67°F. Rain falls on about 9 days. It is one of the warmest months in Chicago.
- Normal high
- 83°F
- Normal low
- 67°F
- Wet days
- 9
- 4.1 in total
- Muggy days
- 11
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 85°F | 81°F |
| Normal low | 68°F | 65°F |
| Chance of a wet day | 31% | 29% |
| Sunrise / sunset | 5:44 am / 8:09 pm | 6:15 am / 7:26 pm |
| Daylight | 14.4 h | 13.2 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical August day
- 6 am68°Fdew point 62°F
- 9 am75°Fdew point 62°F
- Noon79°Fdew point 61°F
- 3 pm80°Fdew point 61°F
- 6 pm77°Fdew point 61°F
- 9 pm74°Fdew point 62°F
NOAA hourly normals (local standard time) from Chicago Midway Airport (7 mi away); average wind 8 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F7 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph15 of 31
- Hot dayshigh 90°F or more5 of 31
- Muggy daysdaily mean dew point 65°F or more11 of 31
- Wet daysat least 0.01 in of rain or melted snow9 of 31
- Notable rainat least 0.10 in7 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 4.1 in; a dry August brings about 2.3 in and a wet one about 5.8 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 1 an inch or more.
How August varies from year to year
- Warmest August, 1991-20201995: average high 89°F
- Coolest August2004: average high 77°F
- Wettest August2014: 9.0 in
- Driest August1996: 0.8 in
- Highest reading102°F (August 2, 1991)
- Lowest reading49°F (August 31, 2009)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 85°F | 83°F | 77°F |
| Normal low | 68°F | 67°F | 59°F |
| Wet days | 10 | 9 | 8 |
| Comfortable days | 6 | 7 | 15 |
| Daylight | 14.9 h | 13.8 h | 12.5 h |
Highs change by -2°F from July and -6°F into September.
Nearby alternatives in August
- Cooler: Sister Bay, WI232 mi · high 75°F · 9 wet days
How Chicago ranks in August
- Normal high249th warmest of 378 cities; 3rd of 8 in Illinois
- Wet days203rd driest of 378
- Comfortable days98th most of 341
What to pack for Chicago in August
- A rain jacket or umbrella – rain on about 9 days
- A swimsuit – about 15 beach days
Heating and cooling
August has 3 heating degree days and 312 cooling degree days (base 65°F), 5% of the year's total heating and cooling demand.
Questions
How hot is Chicago in August?
The normal high is 83°F and the normal low is 67°F. From 1991 to 2020 the hottest August reading was 102°F (August 2, 1991).
Does it rain a lot in Chicago in August?
About 9 days in August have at least 0.01 in of precipitation, and the normal total is 4.1 in. The wettest August in 1991-2020 was in 2014 (9.0 in); the driest was in 1996 (0.8 in).
Is August a good time to visit Chicago?
August ranks 6th of 12 months on our comfort score for Chicago (58 out of 100). It has about 7 comfortable days and about 5 days at 90°F or hotter. The best months are May and September.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Chicago Midway Airport 3SW (USC00111577), 10 mi SW of the city center, 620 ft . NOAA normals and daily records, 1991-2020.
- Frost dates and humidity and wind by hour: Chicago Midway Airport (USW00014819), 6.9 mi SW of the city center, 612 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Chicago Midway Intl Arpt (725340-14819), 7.1 mi SW of the city center, 610 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).