WeatherArchive / Climate averages / Chicago
Chicago weather by month: climate averages
Chicago averages 50°F (10°C) over the year. July is warmest, with highs around 80°F (27°C); January is coldest, with lows near 19°F (-7°C). About 39 inches (982 mm) of precipitation falls on roughly 121 days a year, from 30 years of ERA5 data (1996–2025).
| Month | Avg high | Avg low | Precip. | Days ≥1 mm | Sunshine / day |
|---|---|---|---|---|---|
| January | -0.9°C | -7.2°C | 59.0 mm | 9.1 | 5.5 h |
| February | 0.6°C | -6.6°C | 56.2 mm | 7.8 | 7.0 h |
| March | 5.4°C | -1.5°C | 70.7 mm | 9.9 | 8.5 h |
| April | 11.4°C | 4.3°C | 97.8 mm | 12.0 | 9.3 h |
| May | 17.9°C | 10.8°C | 111.1 mm | 12.1 | 10.5 h |
| June | 24.2°C | 17.3°C | 99.9 mm | 11.9 | 11.9 h |
| July | 26.6°C | 20.2°C | 100.7 mm | 11.2 | 12.3 h |
| August | 25.8°C | 19.8°C | 96.3 mm | 11.0 | 11.6 h |
| September | 22.5°C | 16.2°C | 77.9 mm | 8.7 | 10.0 h |
| October | 15.6°C | 9.5°C | 90.4 mm | 10.0 | 7.9 h |
| November | 8.3°C | 2.6°C | 60.0 mm | 8.3 | 6.1 h |
| December | 2.2°C | -3.3°C | 62.3 mm | 9.4 | 5.1 h |
Record high 1996–2025: 37.4°C on 2022-06-21. Record low: -32.5°C on 2019-01-31.
Source: Open-Meteo Historical Weather API (CC BY 4.0). Values are ERA5 reanalysis model data on a ~9–25 km grid, not readings from a weather station, so a single town’s thermometer can differ by a few degrees and local showers can be missed. Grid cell 41.86, -87.65 at 241 m. For snowfall, humidity and a best-time-to-visit score, open Chicago in the climate tool.
Chicago weather month by month
The wettest month in Chicago is May, averaging 4.4 in (111 mm); the driest is February at 2.2 in (56 mm). May has the most days with at least 1 mm of rain (about 12). July is the sunniest month, with about 12.3 hours of sunshine a day, against 5.1 hours in December. If you like average highs between 64 °F and 82 °F (18–28 °C) with few rainy days, aim for July, August and September.
Planning a particular day? See how often that date was wet or hot over 30 years with the event weather odds, or look up what the weather actually was on any past date in the historical weather archive.
Questions people ask
What is the warmest month in Chicago?
July, with an average daily high of 80°F (27°C) over 1996–2025.
What is the coldest month in Chicago?
January, when nights average about 19°F (-7°C).
What is the rainiest month in Chicago?
May has the most precipitation (about 4.4 in (111 mm)), and May has the most rainy days (about 12 days with 1 mm or more). The driest month is February.
How much sunshine does Chicago get?
About 8.8 hours of bright sunshine a day averaged over the year, from 5.1 h in December to 12.3 h in July. Sunshine here is the model’s estimate of hours with direct sun, not hours of daylight.
What is the best month to visit Chicago for mild weather?
By average high between 64 °F and 82 °F (18–28 °C) and the fewest rainy days: July, August, September. Prices, crowds and events are not included.