Climate
Rancho Cucamonga weather by month
Average highs, lows, rain and snow for every month, from 30 years of weather records.
Average temperatures
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
Best time to visit: April, May, October, when highs are mild and rain is lightest.
Month by month
| Month | High | Low | Rain | Wet days |
|---|---|---|---|---|
| January | 68°F | 45°F | 2.6 in | 5 |
| February | 68°F | 46°F | 3.1 in | 6 |
| March | 72°F | 49°F | 1.6 in | 5 |
| April | 76°F | 51°F | 0.80 in | 4 |
| May | 80°F | 56°F | 0.30 in | 2 |
| June | 86°F | 60°F | 0.00 in | 0 |
| July | 94°F | 65°F | 0.10 in | 1 |
| August | 95°F | 65°F | 0.00 in | 0 |
| September | 91°F | 64°F | 0.10 in | 1 |
| October | 83°F | 57°F | 0.40 in | 2 |
| November | 75°F | 49°F | 0.80 in | 4 |
| December | 67°F | 44°F | 1.9 in | 6 |
NOAA U.S. Climate Normals 1991–2020, Ontario Intl Ap, Ca Us (3.5 mi away, 949 ft). Wet days: days with at least 0.01 in of precipitation.
Questions
What is the hottest month in Rancho Cucamonga?
August, with an average high of 95°F and low of 65°F.
What is the coldest month in Rancho Cucamonga?
December, with an average low of 44°F and high of 67°F.
When does it rain most in Rancho Cucamonga?
February is the wettest month, averaging 3.1 in of precipitation; the year totals about 11.7 inches.
What is the best time to visit Rancho Cucamonga?
For mild weather (highs between 65°F and 85°F) with the least rain, April, May, October.
Where do these numbers come from?
NOAA’s 1991–2020 U.S. Climate Normals for the Ontario Intl Ap weather station, 3.5 miles from downtown: 30-year averages, not a forecast.