Climate of Chicago, United States

Dfa

Köppen-Geiger climate classification: Dfa — Cold, no dry season, hot summer.

Chicago has a mean annual temperature of 10.3 °C and receives 896 mm of precipitation per year (1991–2020 climate normals). The warmest month is July with a mean temperature of 23.6 °C, while January is the coldest month at -3.7 °C. Most precipitation falls in May (101 mm); the driest month is February (42 mm).

Climate Diagram

Climate diagram for Chicago: monthly mean temperature (red line, left axis, °C) and monthly precipitation (blue bars, right axis, mm), 1991–2020 0 0 10 20 20 40 30 60 40 80 50 100 60 120 °C mm J F M A M J J A S O N D

Walter–Lieth diagram: blue bars show monthly precipitation (right axis, mm), the red line shows monthly mean temperature (left axis, °C). Scale: 1 °C ≡ 2 mm.

Climate Table

MonthMean temperature (°C)Precipitation (mm)
January-3.749.4
February-2.242.2
March2.660.6
April8.688.8
May15.0100.5
June20.997.1
July23.693.7
August22.897.9
September19.074.6
October12.281.1
November5.260.2
December-0.449.9
Year10.3895.9

Live Forecast

Looking for the current weather instead of climate averages? Open the live forecast diagrams in WZ Diagrams — 15 weather models, ensemble spread, radar and more.

Data Source

Climate normals and Köppen-Geiger classification: Beck et al. (2023), Scientific Data 10, 724, CC BY 4.0. Period 1991–2020. Classification resolution ≈ 1 km; monthly climate data resolution ≈ 1 km (0.01°, Original 2023 release; predates the January 2026 correction), sampled at the grid cell containing the city coordinates (41.88°, -87.63°). Climate normals describe the long-term average, not current weather.