Chicago, IL Weather Forecast & Climate Guide
Chicago experiences a continental climate with hot, humid summers and cold, snowy winters. The city's location on Lake Michigan significantly influences its weather patterns, moderating temperatures and increasing precipitation.
Climate type: Humid continental (Köppen Dfa)
Chicago Climate Overview
Summer highs average in the low 80s°F (27°C) with high humidity, while winter temperatures often drop below freezing with average lows around 20°F (-7°C). The city receives about 38 inches of precipitation annually, including significant snowfall in winter.
Lake Michigan creates a significant "lake effect" that moderates temperatures year-round but can produce heavy snow in winter. The city experiences rapid weather changes due to its location in the path of many storm systems moving across the Great Plains. Summers can bring severe thunderstorms, while winters feature blizzards and frigid Arctic air masses.
Chicago Weather by Season
spring
Spring in Chicago is famously fickle — snow in April isn't unusual, but so are 80°F days. Temperatures swing wildly as Arctic and Gulf air masses collide over the city.
summer
Summers are hot and humid with highs in the low 80s°F and dewpoints pushing into the 70s. Afternoon and evening thunderstorms are frequent, some of them severe.
fall
Fall brings crisp air, colorful trees, and some of the year's most stable weather. Highs drop from the 70s°F in September to the 40s°F by late November.
winter
Winters are cold, snowy, and windy. Average highs sit in the low 30s°F, lows often drop into the teens, and Arctic outbreaks can plunge temperatures below 0°F. Lake effect and nor'easter-style snowstorms combine for 37 inches of annual snowfall.
Chicago Average Monthly Temperatures
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 32° | 36° | 47° | 59° | 70° | 80° | 85° | 83° | 76° | 63° | 48° | 36° |
| Low °F | 18° | 22° | 32° | 42° | 52° | 62° | 68° | 66° | 58° | 46° | 34° | 23° |
Best Time to Visit Chicago
Late May through early October for warm weather, with September being the sweet spot — warm days, cool nights, and far less humidity than peak summer.
Severe Weather Risks
- Blizzards
- Tornadoes
- Lake-effect snow
- Polar vortex outbreaks
- Severe thunderstorms
Weather Facts About Chicago
- >Chicago's "Windy City" nickname is actually about politicians, not weather — though 10+ mph average winds help.
- >Lake Michigan moderates temperatures year-round, keeping lakefront neighborhoods cooler in summer and milder in winter.
- >The record low in Chicago is -27°F, set during the 1985 polar vortex.
Chicago Weather FAQ
When is the best time to visit Chicago weather-wise?
September and early October deliver warm days in the 70s°F, cool nights, low humidity, and low rain chances. June is also excellent before summer humidity peaks.
How cold does Chicago get in winter?
Average winter highs are in the low 30s°F with lows in the teens. Arctic outbreaks can push wind chills below -30°F. The city averages about 37 inches of snow per winter.
Does Chicago get tornadoes?
Yes — Chicago sits at the northeastern edge of Tornado Alley, and the metro area averages several tornado warnings per year. Most occur between April and June.
What is the "lake effect" in Chicago?
Cold air passing over warmer Lake Michigan picks up moisture and dumps it as heavy snow on the downwind shore. Chicago sees lake-effect snow less often than cities like Buffalo but it can still produce intense bursts.