San Antonio (TX) Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in San Antonio, Texas, United States of America. The figures are based on a 30-year period (1990–2020) to provide a reliable average. Now, let's explore all the details to give you a full picture.

Generally, San Antonio has a moderate amount of precipitation, averaging 818 mm (32 in) of rainfall annually.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

The seasons in San Antonio, bring significant changes in precipitation. The wettest month, May, receives high rainfall, with an average of 130 mm (5.1 in) of precipitation. This rainfall is distributed across 9 rainy days.

May, the wettest month, has a maximum daytime temperature of 31°C (88°F). The city receives 222 hours of sunshine in this period. During the driest month December you can expect a temperature of 18°C (64°F). For more detailed insights into the city's temperatures, visit our San Antonio Temperature page.

San Antonio's average annual precipitation is 818 mm (32 in). Let's compare this to some popular worldwide tourist destinations:

Boston, USA, experiences 1238 mm (49 in) of annual precipitation, including significant snowfall during the winter.

Osaka, Japan, experiences 1507 mm (59 in) of rainfall annually, spread across the year with wetter summers.

In Tokyo, Japan, the average annual precipitation is 1528 mm (60 in), with significant summer rains due to typhoon season.

Ho Chi Minh City, Vietnam, receives 1955 mm (77 in) of annual rainfall, with a pronounced wet season from May to November, typical of its tropical monsoon climate.

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.

The proximity of a location to a large body of water can significantly affect its rainfall patterns:

• Ocean Influence: Coastal regions typically receive more rainfall due to the presence of moisture-laden winds from the ocean. These regions tend to have more humid climates and experience more frequent precipitation, especially in winter.
• Continental Climates: Areas further from the sea, such as inland or continental regions, experience less frequent rainfall and more extreme seasonal variations in precipitation.

• The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
• Approximately 70% of lightning bolts strike land rather than oceans.
• A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.

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.