Chicago, Illinois Weather
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Climate of Chicago: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Chicago, with average daytime highs around 25°C. February is the coolest, when nights typically fall to about -5°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 30°C, so the seasons feel very different from each other.
The area receives about 980 mm of rain in a typical year. Most of it falls from May to June and August, and May is the wettest month at roughly 117 mm.
For outdoor plans and travel, July and September usually offer the most comfortable weather in Chicago, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 0° | -5° | 48 mm | 86% |
| Feb | 0° | -5° | 54 mm | 84% |
| Mar | 5° | -1° | 62 mm | 82% |
| Apr | 10° | 4° | 95 mm | 81% |
| May | 15° | 9° | 117 mm | 83% |
| Jun | 21° | 15° | 102 mm | 81% |
| Jul | 25° | 20° | 95 mm | 78% |
| Aug | 25° | 20° | 105 mm | 77% |
| Sep | 22° | 16° | 86 mm | 76% |
| Oct | 15° | 10° | 99 mm | 77% |
| Nov | 9° | 4° | 61 mm | 80% |
| Dec | 3° | -2° | 58 mm | 85% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Chicago. Values describe typical conditions, not a forecast.
About Chicago weather
Chicago lies in Illinois's humid continental climate, shaped by its Great Lakes and prairie geography — about 285 km north-east of Springfield. Expect warm, humid summers (June–August). Winter brings cold winters (December–February) with regular snow, colder near Lake Michigan. This page shows live, auto-refreshing weather for Chicago: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
Chicago is about 285 km north-east of Springfield, in Illinois.
Chicago sees cold winters (December–February) with regular snow, colder near Lake Michigan.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Chicago's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Chicago, with average daytime highs of about 25°C and nights around 20°C.
The coldest nights come in February, when the average low is about -5°C and daytime highs reach around 0°C. Frost is possible on clear, calm nights.
Chicago receives about 980 mm of rain in a typical year. May is the wettest month at roughly 117 mm, and the main rainy period is May to June and August.
July and September usually offer the most comfortable weather in Chicago, with mild daytime temperatures and little rain.
In November Chicago typically sees daytime highs near 9°C and lows near 4°C, with about 61 mm of rain over the month and average humidity around 80%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
The current temperature for Chicago updates automatically at the top of this page — scroll to the hourly strip below to see how it's expected to change over the day.
Chicago's day-to-day weather follows the broader pattern of Illinois described above. See the hourly weather forecast or the air quality index for more detail.