Ontario, CA weather in July
Expect hot, dry weather in Ontario in July, with highs near 94°F and lows near 65°F. Rain falls on about 1 day. It is one of the warmest months in Ontario. Plan outdoor time for mornings and evenings.
- Normal high
- 94°F
- Normal low
- 65°F
- Wet days
- 1
- 0.05 in total
- Muggy days
- 1
- dew point 65°F+
How July changes from start to finish
| July 1 | July 31 | |
|---|---|---|
| Normal high | 91°F | 95°F |
| Normal low | 63°F | 65°F |
| Chance of a wet day | 1% | 2% |
| Sunrise / sunset | 5:42 am / 8:06 pm | 6:01 am / 7:52 pm |
| Daylight | 14.4 h | 13.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical July day
- 6 am66°Fdew point 57°F
- 9 am80°Fdew point 55°F
- Noon90°Fdew point 53°F
- 3 pm92°Fdew point 54°F
- 6 pm84°Fdew point 54°F
- 9 pm72°Fdew point 56°F
NOAA hourly normals (local standard time) from March AFB (26 mi away); average wind 6 mph; clear or few clouds in 81% of daytime hours, mostly cloudy or overcast in 11%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F1 of 31
- Hot dayshigh 90°F or more23 of 31
- Muggy daysdaily mean dew point 65°F or more1 of 31
- Wet daysat least 0.01 in of rain or melted snow1 of 31
- Notable rainat least 0.10 in0 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per July, counted from daily records for each year 1991-2020.
Rain in July
Normal precipitation is 0.05 in; a dry July brings about 0.0 in and a wet one about 0.04 in (25th and 75th percentiles). Days with half an inch or more are rare.
How July varies from year to year
- Warmest July, 1991-20202018: average high 99°F
- Coolest July2010: average high 88°F
- Wettest July2015: 0.6 in
- Driest July1998: no measurable precipitation
- Highest reading117°F (July 6, 2018)
- Lowest reading56°F (July 9, 2010)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
July compared with June and August
| June | July | August | |
|---|---|---|---|
| Normal high | 86°F | 94°F | 95°F |
| Normal low | 60°F | 65°F | 65°F |
| Wet days | 0 | 1 | 0 |
| Comfortable days | 7 | 1 | 0 |
| Daylight | 14.4 h | 14.2 h | 13.4 h |
Highs change by +8°F from June and +1°F into August.
Nearby alternatives in July
- Warmer: Palm Springs, CA65 mi · high 109°F · 1 wet day
- Cooler: West Covina, CA16 mi · high 82°F · 1 wet day
How Ontario ranks in July
- Normal high70th warmest of 378 cities; 18th of 60 in California
- Wet days37th driest of 378
- Comfortable days202nd most of 340
What to pack for Ontario in July
- Light, breathable clothing – highs near 94°F
- Layers – afternoons near 94°F but nights near 65°F
- Sunglasses and sunscreen – about 14.2 hours of daylight and highs near 94°F
Heating and cooling
July has 0 heating degree days and 442 cooling degree days (base 65°F), 14% of the year's total heating and cooling demand.
Questions
How hot is Ontario in July?
The normal high is 94°F and the normal low is 65°F. From 1991 to 2020 the hottest July reading was 117°F (July 6, 2018).
Does it rain a lot in Ontario in July?
About 1 days in July have at least 0.01 in of precipitation, and the normal total is 0.05 in. The wettest July in 1991-2020 was in 2015 (0.6 in); the driest was in 1998, with no measurable precipitation.
Is July a good time to visit Ontario?
July ranks 11th of 12 months on our comfort score for Ontario (44 out of 100). It has about 1 comfortable day and about 23 days at 90°F or hotter. The best months are March, April and May.
Where the numbers come from
- Temperature, rain and frost dates: Ontario Intl Airport (USW00003102), 2.9 mi E of the city center, 949 ft (52 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Snowfall and snow depth: San Gabriel Canyon PH (USC00047776), 16 mi WNW of the city center, 744 ft (257 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: March AFB (USW00023119), 26 mi ESE of the city center, 1,516 ft (515 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: March Air Reserve Base (722860-23119), 26 mi ESE of the city center, 1,536 ft (535 ft higher than the city). Hourly observations, 1991-2020.