Foster City (CA) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Foster City (CA). The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s explore all the details to give you a full picture.

Foster City has a relatively dry climate with low precipitation, averaging 401 mm of rainfall annually.

Monthly Precipitation Levels

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

The seasons in Foster City, bring significant changes in precipitation. The wettest month, December, receives moderate rainfall, with an average of 96 mm of precipitation.

This rainfall is distributed across 12 rainy days. In contrast, the driest month, July, experiences much less rainfall, totaling 0 mm over 0 rainy days. These distinct seasonal differences provide diverse experiences throughout the year.

December, the city’s wettest month, has a maximum daytime temperature of 14°C and receives 160 hours of sunshine. During the driest month July you can expect a temperature of 24°C. For more detailed insights into the city’s temperatures, visit our Foster City 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

Foster City’s average annual precipitation is 401 mm. Let’s compare this to some popular worldwide tourist destinations:

Seville, Spain, experiences 541 mm of rainfall annually, with wet winters and dry summers typical of southern Spain.

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

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

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.

How Does Precipitation Affect Local Climate?

Precipitation has a very strong role in determining the local climate and ecosystem:

• Rainy Seasons: Many parts of the world have well-defined wet seasons where precipitation is distinctly higher. These are normally accompanied by lush vegetation and temperature patterns.
• Dry Seasons: In areas where the climate is either desert or Mediterranean, the amount of precipitation is drastically reduced, leading to a shortage of water and arid conditions.

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