Climate averages 1991–2020
Rancho Cucamonga weather
in July.
A hot, very dry month: the 2nd warmest and the 2nd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a hot month in Rancho Cucamonga: daytime highs average 32.3°C and nights cool to about 18.7°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 2.2 mm of rain on fewer than one day, which makes July a very dry month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 11 min on an average July day.
The nearest other city in this atlas is Ontario (7 km away). In July its highs average 31.8°C, 0.5°C cooler than Rancho Cucamonga, with 1.7 mm of rain.
Among the 498 cities listed in the United States, Rancho Cucamonga ranks joint 122nd of 498 for the warmest July highs and joint 71st of 498 for the driest July (rainfall, lowest first). The mean July high of those 498 cities is 30.3°C; Rancho Cucamonga is 2.0°C warmer than that mean.
From July to August, average highs rise by 1.0°C to 33.3°C, and monthly rainfall falls from 2.2 mm to 1.1 mm.
The annual picture
July in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Rancho Cucamonga climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 17.2°C5.6°C | 5.6°C | 96 | 6.6 | 10.210 h |
| February | 17.5°C6.1°C | 6.1°C | 111 | 7.4 | 10.911 h |
| March | 19.5°C7.7°C | 7.7°C | 68 | 6.8 | 12.012 h |
| April | 22.0°C9.4°C | 9.4°C | 32 | 4.6 | 13.013 h |
| May | 24.8°C12.2°C | 12.2°C | 15 | 2.6 | 13.914 h |
| June | 28.9°C15.3°C | 15.3°C | 3.4 | 0.5 | 14.414 h |
| July, selected | 32.3°C18.7°C | 18.7°C | 2.2 | 0.5 | 14.214 h |
| August | 33.3°C19.2°C | 19.2°C | 1.1 | 0.3 | 13.413 h |
| September | 31.4°C17.4°C | 17.4°C | 5.5 | 1.2 | 12.412 h |
| October | 26.4°C13.2°C | 13.2°C | 22 | 3.1 | 11.411 h |
| November | 21.3°C8.8°C | 8.8°C | 30 | 3.5 | 10.410 h |
| December | 16.9°C5.4°C | 5.4°C | 67 | 5.8 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
July in nearby cities
- Ontario in JulyUnited States · 7 kmHigh 31.8°C · Low 18.6°C · 1.7 mm rain
- Chino in JulyUnited States · 14 kmHigh 30.8°C · Low 18.2°C · 1.7 mm rain
- Fontana in JulyUnited States · 15 kmHigh 32.4°C · Low 18.7°C · 2.2 mm rain
- Pomona in JulyUnited States · 16 kmHigh 30.9°C · Low 17.9°C · 1.7 mm rain
- Chino Hills in JulyUnited States · 20 kmHigh 30.1°C · Low 17.8°C · 1.7 mm rain
- Riverside in JulyUnited States · 25 kmHigh 32.7°C · Low 18.9°C · 2.2 mm rain
- Corona in JulyUnited States · 26 kmHigh 32.0°C · Low 18.5°C · 2.2 mm rain
- San Bernardino in JulyUnited States · 28 kmHigh 32.9°C · Low 19.6°C · 12 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Rancho Cucamonga) is explained once on the Rancho Cucamonga year overview and on the Sources, method and limits page.
Riverside, Fontana and Corona lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.