Sunnyvale enjoys a classic Mediterranean climate (Köppen climate classification: _Csb_), characterized by mild, wet winters and warm, very dry summers.
- **Temperatures:** Summer highs average in the upper 70s to low 80s Fahrenheit (25–28°C), while winter lows rarely drop below 40°F (4°C). - **Rainfall:** The city receives an average of 14 to 15 inches of rain annually, almost exclusively between November and April. - **Snowfall:** Snow is exceptionally rare in the city limits. - **Natural Disasters:** The primary natural risk in Sunnyvale, as with much of California, is earthquakes, given its proximity to the San Andreas and Hayward faults. - **Best Time to Visit:** September and October offer beautiful, crisp weather, though the mild climate makes Sunnyvale pleasant to visit year-round.