Santa Rosa (CA) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Santa Rosa (CA). The numbers are calculated over a 30-year period to provide a reliable average. Let's now guide you through the details for a complete overview.

Generally, Santa Rosa has a moderate amount of precipitation, averaging 713 mm of rainfall 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, December receives substantial rainfall, averaging 145 mm of precipitation, recorded across 13 rainy days.

In contrast, the drier season, August brings less rainfall, with 0.3 mm over a single rainy day.

December, the city’s wettest month, has a maximum daytime temperature of 14°C. During the driest month August you can expect a temperature of 27°C. For more detailed insights into the city’s temperatures, visit our Santa Rosa 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

Santa Rosa’s average annual precipitation is 713 mm. Let’s compare this to some popular worldwide tourist destinations:

Chicago, USA, sees an annual precipitation of 1062 mm, with rain and snow contributing to its humid climate.

Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with 1000 mm of annual rainfall, mostly in the summer.

In Brisbane, Australia, the annual precipitation is 979 mm, making it wetter than Sydney.

Kuala Lumpur, Malaysia, receives 2529 mm of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.

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

• Mawsynram in India is noted as being the wettest place on earth, with over 11 meters of rain falling every year.
• In contrast, Antofagasta in Chile is among the driest places on the planet, getting less than 0.1mm per year, with some years recording virtually no rainfall.
• Nearly 1,650 thunderstorm cells are estimated over the planet at any given time.

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