Sebastopol (CA) Temperature by Month

Sebastopol in California, United States of America sees significant seasonal temperature differences, with daytime highs between 14°C (57°F) in December and 29°C (84°F) in September, averaging 22°C (72°F) annually. Explore the full monthly breakdown below.

With significant temperature fluctuations, Sebastopol enjoys distinct seasons year-round. Nighttime lows range from 9°C (48°F) in September to 3°C (37°F) in December.

The chart below illustrates the average maximum day and minimum night temperatures in Sebastopol by month:

Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM. September, the warmest month, sees 275 hours of sunshine.

The chart below shows the average temperature throughout the year:

Sebastopol's average annual maximum temperature is 22°C (72°F). To put that in context, here's how it compares to a few well-known destinations:

Seville, Spain averages 23°C (73°F) a year, one of the warmer cities in Western Europe, with long hot summers.

Reykjavík, Iceland averages 9°C (48°F) a year, mild summers by Icelandic standards, but cold winters and frequent wind.

Osaka, Japan averages 22°C (72°F) annually, with hot humid summers, mild winters, and pleasant spring and autumn seasons.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

For more on Sebastopol's weather, including monthly rainfall, sunshine hours, and humidity, visit our Sebastopol climate page.