St. Louis (MO) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in St. Louis (MO). The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s break down all the details for a clearer picture.

St. Louis experiences significant rain/snowfall throughout the year, averaging 1116 mm of precipitation annually.

Monthly Precipitation Levels

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

Significant seasonal changes in precipitation occur throughout the year. During the wet season, June receives substantial rainfall, averaging 136 mm of precipitation, recorded across 12 rainy days.

In contrast, the drier season, January brings less snow/rainfall, with 50 mm over 8 snowy/rainy days.

June, the city’s wettest month, has a maximum daytime temperature of 30°C and receives 293 hours of sunshine. During the driest month January you can expect a temperature of 5°C. For more detailed insights into the city’s temperatures, visit our St. Louis 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

St. Louis’s average annual precipitation is 1116 mm. Let’s compare this to some popular worldwide tourist destinations:

New York City, USA, receives 1276 mm of rainfall annually, with precipitation evenly distributed throughout the year.

In Shanghai, China, the annual average precipitation is 1347 mm, with a humid subtropical climate.

Perth, Australia, receives 565 mm of rainfall annually, mostly during the winter months.

Bangkok, Thailand, experiences a tropical monsoon climate with 1668 mm of annual rainfall, with the heaviest precipitation occurring during September and October.

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.

Interesting weather facts

• "Ginger" was the longest-lasting Atlantic tropical storm, which spun around the open ocean for 28 days in 1971.
• The world's largest snowflake was recorded in the Guinness Book of Records, at 38 cm wide and 20 cm thick. The snowflake fell at Fort Keogh, Montana, USA, on 28 January 1887.
• The greatest snowfall recorded was on Mt. Rainier, Washington State, USA—over 31.5 meters fell during the winter of 1972.

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