Ontario, California Weather:
Thursday, May 21, 2026
Partly Sunny with Showers
Day 73°
Night 52°
Precipitation 1 %
Wind 6 mph
Weather Forecast History
Last Year's Weather on This Day (May 21, 2025)
Sunny Weather

Day

91°

Night

61°

Wind

7 mph

UV Index

11

Precipitation

1 %