Rancho Cucamonga, California Weather:
Monday, September 21, 2026
Sunny Weather
Day 84°
Night 66°
Precipitation 2 %
Wind 5 mph
UV Index (0 - 11+) 7
Weather Forecast History
Last Year's Weather on This Day (September 21, 2025)
Cloudy Night

Day

81°

Night

64°

Wind

4 mph

Precipitation

2 %