Keystone (SD) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Keystone (SD). The numbers are calculated over a 30-year period to provide a reliable average. Let’s explore the details in depth to provide you with a complete overview.

Generally, Keystone receives mid-range precipitation levels, with 536 mm annually.

Monthly Precipitation Levels

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

The seasons in Keystone, bring significant changes in precipitation. The wettest month, May, receives high rainfall, with an average of 114 mm of precipitation.

This rainfall is distributed across 15 rainy days. In contrast, the driest month, January, experiences much less snowfall, totaling 8.4 mm over 6 snowy days. These distinct seasonal differences provide diverse experiences throughout the year.

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

Keystone’s average annual precipitation is 536 mm. Let’s compare this to some popular worldwide tourist destinations:

In Barcelona, Spain, the average annual precipitation is 644 mm, evenly distributed across the year with no extreme wet or dry seasons.

Beijing, China, receives 560 mm of annual precipitation, concentrated in the summer months.

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

Mumbai, India, experiences a tropical monsoon climate with 1860 mm of annual rainfall, with the majority of precipitation happening during the monsoon season from June to September.

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 Keystone (SD)’s weather, including sunshine hours, humidity levels, and temperature data, visit our Keystone (SD) Climate page.