Chicago (IL) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Chicago (IL). The numbers are calculated over a 30-year period to provide a reliable average. Let's now guide you through the details for a complete overview.

Chicago has a relatively rain/snowy climate with high precipitation levels, averaging 1062 mm of rain/snowfall annually.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm)

The climate in Chicago shows significant variation throughout the year. Expect 126 mm of precipitation during the wettest month June, distributed over 14 rainy days.

In contrast, January offers drier and sunnier days, with around 50 mm of snowfall over 10 snowy days.

June, the wettest month, has a maximum daytime temperature of 26°C. The city receives 311 hours of sunshine in this period. During the driest month January you can expect a temperature of -1°C. For more detailed insights into the city’s temperatures, visit our Chicago Temperature page.

Annual Precipitation in the United States of America

The map below shows the annual precipitation across the United States of America. You can also select the different months in case you are interested in a specific month.

Amsterdam Precipitation Compared World Wide

Chicago’s average annual precipitation is 1062 mm. Let’s compare this to some popular worldwide tourist destinations:

Athens, Greece, receives an average annual precipitation of 400 mm, making it one of the drier Mediterranean climates with rainfall mostly in winter.

In Seoul, South Korea, the average annual precipitation is 1237 mm, with most rain falling during the summer monsoon season.

Melbourne, Australia, has 690 mm of rainfall annually, spread fairly evenly throughout the year.

Singapore, situated near the equator, gets 2581 mm of rainfall annually, with no distinct dry season and consistent monthly precipitation.

How is Precipitation Measured?

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Global Warming and Precipitation

Climate change is affecting precipitation patterns worldwide, including Chicago (IL):

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

For more detailed information about Chicago (IL)’s weather, including sunshine hours, humidity levels, and temperature data, visit our Chicago (IL) Climate page.