Tuesday, July 21, 2026 · Hour-by-hour forecast updated 6:24 AM PDT
61°F and clear at peak. Wind 2 mph from the NW, dew point 53°F.
FitCast texts you tomorrow's hour-by-hour forecast every evening so you know exactly what to expect before your alarm goes off.
Based on today's FitScore analysis, the best time to run is 5 AM–7 AM with a peak FitScore of 93/100. Check the hourly breakdown above for detailed conditions throughout the day.
The best months for running in Sunnyvale are June, July, August, September. The most challenging months are typically November, December. Mild summers with low humidity make for ideal running. Watch for marine layer fog in coastal areas.
FitScore rates each hour from 0–100 for outdoor exercise based on temperature, humidity, dew point, wind, precipitation probability, UV index, and air quality. Higher scores mean better conditions.