Rain and storageGuide
How much rain Sonoma County gets
Santa Rosa averages 31.5 inches a year. Petaluma gets 25.6. Healdsburg gets 42.8. Most of it falls from November to March.
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What it means for you
- Rain nearly doubles from Petaluma to Healdsburg. Your ZIP matters.
- Most rain falls in the cool months. Your barrel or basin sits idle all summer.
- A year can be less than half or nearly double the average. Size a tank for the dry year.
That chart is the long Santa Rosa record, 1889 to 2000, at the Santa Rosa gauge (DWR station F90 7965 00). The driest year was 1920 and the wettest was 1890.
Plug in your roof
The Santa Rosa figure in the table comes from NOAA normals as shown on Wikipedia, which also gives 32.2 inches in its text. Guerneville is a National Weather Service figure with no period stated. These are town stations, so hill and coastal spots can differ a lot. Coastal ZIPs have no close station yet.
Sources
- Santa Rosa climate table (NOAA normals)
- Healdsburg climate table (NOAA normals)
- Petaluma climate table
- Sonoma climate table (NOAA normals)
- Cloverdale climate table (NOAA normals)
- Guerneville climate text (National Weather Service)
- KRIS Russian River database, Santa Rosa annual rainfall 1889 to 2000
Checked 2026-10-11. Rules and programs change. If something here is out of date, the source above wins. Spot an error? See our corrections policy.
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