San Antonio (TX) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in San Antonio (TX). 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.

Generally, San Antonio has a moderate amount of precipitation, averaging 818 mm of rainfall annually.

Monthly Precipitation Levels

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

The seasons in San Antonio, bring significant changes in precipitation. The wettest month, May, receives high rainfall, with an average of 130 mm of precipitation.

This rainfall is distributed across 9 rainy days. In contrast, the driest month, December, experiences much less rainfall, totaling 34 mm over 8 rainy days. These distinct seasonal differences provide diverse experiences throughout the year.

May, the city’s wettest month, has a maximum daytime temperature of 31°C. During the driest month December you can expect a temperature of 18°C. For more detailed insights into the city’s temperatures, visit our San Antonio 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

San Antonio’s average annual precipitation is 818 mm. Let’s compare this to some popular worldwide tourist destinations:

The climate in San Francisco, USA, is influenced by coastal weather, with 469 mm of rainfall mostly during the winter months.

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

Adelaide, Australia, enjoys 511 mm of annual precipitation, with dry summers and wet winters.

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 San Antonio (TX)’s weather, including sunshine hours, humidity levels, and temperature data, visit our San Antonio (TX) Climate page.