Climate - Santa Rosa (California)

The climate of Santa Rosa is mild oceanic, with mild, rainy winters and warm, sunny summers, but with cool nights.
The city is located 80 km (50 mi) northwest of San Francisco, and approximately 30 km (20 mi) away from the ocean. We are near the so-called North Coast of California, where the climate is more humid than in the central-southern part of the State. In the cold semester, fog often forms at night and in the early morning. From November to March, rainfall is also frequent. On the coldest nights of the year, the temperature generally drops to -3/-5 °C (23/26.5 °F), even though in December 1990, it dropped to -9 °C (16 °F).
In the warm half-year, there are strong temperature variations between night and day, so, even if it can get hot during the day, nights are generally cool (or even a little cold). Even in summer, fog can form at night and in the morning, while the ocean breeze cools the air in the afternoon and evening.
On the hottest days of the year, the temperature can reach 38/40 °C (100/104 °F), and this can also happen in September. In September 2017, it reached 43 °C (109.5 °F). These torrid temperatures occur when the wind blows from the deserts of California.
The average temperature of the coldest month (January) is of 8.1 °C (47 °F), that of the warmest month (August) is of 19.8 °C (68 °F). Here are the average temperatures.

Precipitation amounts to 820 millimeters (32.3 inches) per year: so, it is at an intermediate level. It ranges from 0 mm (0 in) in the driest months (July, August) to 155 mm (6.1 in) in the wettest ones (February, December). Here is the average precipitation.

On the coast to the west of Santa Rosa, the sea is cold even in summer, and the air too is much cooler: highs are below 20 °C (68 °F) even in the height of summer. Here is the average sea temperature in Bodega Bay.

Best Time

Santa Rosa can be visited from May to October. In May and October, it is rarely too hot, but sometimes it can rain. From June to September, the temperatures are generally pleasant (warm during the day and cool at night), but sometimes it can get very hot.

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