Sunnyvale Weather in September

September in Sunnyvale averages 27°C (81°F) during the day and 14°C (57°F) at night. With only 2.8 mm (0.1 in) of rainfall expected on average, it's a largely dry month.

Rainfall in Sunnyvale in September

Historically, approximately a single day this month are expected to have rain, averaging 2.8 mm (0.1 in). If rain does fall, it tends to be very light and barely worth getting out an umbrella for.

Temperature in Sunnyvale in September

The temperature in Sunnyvale in September is excellent. Daytime highs reach 27°C (81°F), with nights dropping to 14°C (57°F). Experience the summer season in September. The days can feel warmer than the evenings, so packing for both parts of the day is a good idea. With overnight lows of 14°C (57°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep. It's the warmest month of the year on average, so summer clothing is the way to go.

Sunshine in Sunnyvale in September

The days are predominantly sunny, with an estimated total of around 270 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.

If your ideal day consists of dry skies and pleasant temperatures, April, May, June, July, August, September and October typically offer the best circumstances for Sunnyvale.