Fullerton, California Weather:
Monday, September 21, 2026
Sunny Weather
Day 81°
Night 66°
Precipitation 1 %
Wind 5 mph
UV Index (0 - 11+) 6
Weather Forecast History
Last Year's Weather on This Day (September 21, 2025)
Rainy Weather

Day

79°

Night

64°

Wind

4 mph

Precipitation

49 %