Chicago, Illinois Weather History

Illinois, United States  •  45 yrs data 📍 41.8675°N, 87.6745°W
°F / °C
☀️

Quick Climate Facts

(1981 – 2025)
Hottest Month
🔥
Aug
Avg 72.5°F
Min 60.5°F
Max 84.5°F
Coldest Month
❄️
Jan
Avg 24.8°F
Min 5.1°F
Max 44.4°F
Wettest Month
🌧️
May
106 mm
Driest Month
🏜️
Jan
48 mm
Most Humid
💧
Jan
87%
Least Humid
🌬️
Sep
75%
Highest Ever
🌡️
94.5°F
Jul 2012
Lowest Ever
🧊
-19.2°F
Jan 1982
Monthly Climate Data
Month 🌤️ High Low Avg Humid % Rain (mm) Wind (m/s) Solar (kWh/m²)

Showing average climate conditions across 45 years (1981–2025)

🌍 Weather in Chicago Across Seasons

❄️ Winter in Chicago

January is Chicago's coldest month, with average lows reaching 5.2°F.
🌡️ December to February (avg)  ·  8.6°F46.9°F

🧥 Pack heavy layers and prepare for snow — this is a Severe Winter destination.

☀️ Summer in Chicago

Summer temperatures in Chicago peak in August, climbing to 84.6°F.
🌡️ July to September (avg)  ·  57°F83.1°F

🌤️ Conditions are ideal for outdoor activities throughout the day in this Mild Summer.

🌧️ Rainy Season in Chicago

Chicago sees its highest rainfall in May, receiving approximately 106 mm of precipitation.
🌧️ May to August (avg)  ·  up to 106 mm

☔ Moderate Rainfall expected — carry rain gear and plan outdoor activities around these months.

📅 Monthly Averages

🌡️ Temperature Patterns

Monthly averages · 1981–2025 climate normals · °F

🌡️ Chicago Monthly Temperature Guide

Aug is the hottest month in Chicago, with average highs reaching 84.5°F, while Jan is the coldest with lows dropping to 5.1°F.

Temperatures rise steadily from spring, peak in Aug, and gradually decline through fall into winter.

These seasonal patterns make summer ideal for outdoor activities, while winters bring freezing conditions and heavy snowfall.

🌧️ Rainfall Distribution

Monthly rainfall · 1981–2025 seasonal trends · mm/month

💨 Humidity & Wind Speed

Monthly averages · 1981–2025

💧 Rainfall & Humidity in Chicago

Chicago receives its highest rainfall in May, while humidity peaks during winter months.
🌧️ Wettest: May — 106 mm ☀️ Driest: Jan — 48 mm

💧 Humidity peaks at 87% in Jan · annual avg 81%

🌍 Climate Summary

Avg Annual Temp:49.6°F
Avg Annual Rainfall:967 mm
Avg Humidity:81%
Data Period:1981 – 2025

Chicago Climate Overview

Chicago has a temperate climate with warm summers and freezing winters.

Temperatures peak in Aug and drop to their lowest in Jan, while rainfall is highest during spring and early summer months.

Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions.

📈 Yearly Trends

The warmest year in Chicago's recorded history was 2012 (avg: 54.7°F), while the coldest year was 1982 (avg: 44.8°F), based on annual average temperatures.

📊 Key Climate Trends

🌡️ Annual Temperature Trend

View Range:

Average annual high/low · Last 10 years · °F

Chicago's temperatures has remained relatively stable over the past decade. The highest recorded temperature reached 94.5°F in Jul 2012, while the lowest dropped to -19.2°F in Jan 1982.

🌧️ Annual Precipitation

View Range:

Total annual precipitation · Last 10 years · mm/year

Annual rainfall in Chicago shows noticeable variation. Rainfall has decreased in recent years compared to earlier periods.
📋 Yearly Climate Data Overview

🔥 hottest  ·  ❄️ coldest  ·  🌧️ wettest

Year Min Temp Avg Temp Max Temp Rainfall (mm) Avg Humidity Avg Wind

🏙️ Other Cities in Illinois

Looking for another state? 🇺🇸 Explore All US States & Cities →

❓ Frequently Asked Questions

What is the hottest month in Chicago?
Based on 45 years of data (1981–2025), Aug is typically the hottest month in Chicago, Illinois, with average high temperatures around 84.5°F.
What is the coldest month in Chicago?
Jan is the coldest month in Chicago, with average low temperatures around 5.1°F.
What is the rainiest month in Chicago?
May receives the most rainfall with approximately 106 mm, while Jan is the driest with 48 mm.
What was the highest temperature ever recorded in Chicago?
The highest recorded temperature was 94.5°F in Jul 2012. This is part of the historical record spanning 1981–2025.
What was the lowest temperature ever recorded in Chicago?
The lowest recorded temperature was -19.2°F in Jan 1982.
How many years of data does this page cover?
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
How much sunlight does Chicago get?
Chicago receives the most sunlight in Jun with an average solar radiation of 6.06 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning, agriculture, and understanding seasonal sunshine availability in Illinois.
Where does this weather data come from?
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.

📚 Data Source

All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.

Parameters included:
  • Temperature (Min, Max)
  • Precipitation
  • Relative Humidity
  • Wind Speed
  • Solar Radiation
Data specifications:
  • Resolution: Monthly
  • Spatial: 0.5° × 0.625°
  • Source: MERRA-2
  • Coverage: 1981–2025
  • Years: 45