The hottest month in Chicago is typically July, with daytime highs averaging around 27.3°C (81°F), based on 10 years of historical weather data. Overnight lows during this period average near 19.5°C (67°F).

What is the coldest month in Chicago?

The coldest month in Chicago is typically January, with overnight lows averaging around -6.7°C (20°F) and daytime highs near 0.2°C (32°F), based on 10 years of historical weather data. Freezing overnight temperatures are common during this month, so plan for icy conditions in the early morning.

Does Chicago have a rainy season?

Chicago doesn't have a sharply defined rainy season rainfall is fairly spread across the year based on 10 years of historical data. July is the wettest month on average (about 152 mm), while February is the driest (about 59 mm).

What's the best time of year to visit Chicago?

The best time to visit Chicago is typically September, when daytime highs average a comfortable 23.9°C (75°F). Rainfall during this window averages around 92 mm, one of the lighter, more comfortable stretches of the year. This is based on 10 years of historical weather data.

Is Chicago's air quality safe right now?

As of the latest reading, Chicago's air quality index (AQI) is 13, rated "Good", based on the nearest monitoring station. Air quality is considered satisfactory, with little to no health risk.

Atmospheric Details

Wind

9 km/h

NNE · Light Breeze · Max 14 km/h

Humidity

64 %

Comfortable

UV Index

Moderate

Visibility

10 km

Excellent

Pressure

994 hPa

Low · change likely

Dew Point

15°C

Somewhat humid

Today vs Normal

23°C+1° above normal

The long-term average high for today is 22°C.

12 of the last 20 days with published data ran above normal.

It continues that pattern - today's forecast is also running above normal.

Red = above normal, blue = at or below · last 12 days

Air Quality

Moderate

Air quality is acceptable for most people. Unusually sensitive individuals should consider reducing prolonged or heavy outdoor exertion.

Health & Activity Advice

✅ Good for Outdoors

UV index is 4 today — moderate. Sunscreen is worth using for extended time outside, but no special precautions are needed for short trips.

Air quality is acceptable for most people. Unusually sensitive individuals should consider reducing prolonged or heavy outdoor exertion.

Conditions are comfortable for outdoor activity at most points during the day today.