Ontario, CA weather in April
Ontario is mild and mostly dry in April: highs average 76°F and nights drop to about 51°F. Expect about 4 wet days. A great month for outdoor plans.
- Normal high
- 76°F
- Normal low
- 51°F
- Wet days
- 4
- 0.8 in total
- Muggy days
- 0
- dew point 65°F+
How April changes from start to finish
| April 1 | April 30 | |
|---|---|---|
| Normal high | 74°F | 78°F |
| Normal low | 50°F | 53°F |
| Chance of a wet day | 13% | 10% |
| Sunrise / sunset | 6:37 am / 7:11 pm | 6:02 am / 7:33 pm |
| Daylight | 12.6 h | 13.5 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 April day
- 6 am49°Fdew point 44°F
- 9 am63°Fdew point 43°F
- Noon71°Fdew point 40°F
- 3 pm73°Fdew point 41°F
- 6 pm65°Fdew point 43°F
- 9 pm56°Fdew point 45°F
NOAA hourly normals (local standard time) from March AFB (26 mi away); average wind 6 mph; clear or few clouds in 62% of daytime hours, mostly cloudy or overcast in 30%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F16 of 30
- Hot dayshigh 90°F or more3 of 30
- Muggy daysdaily mean dew point 65°F or more0 of 30
- Wet daysat least 0.01 in of rain or melted snow4 of 30
- Notable rainat least 0.10 in2 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per April, counted from daily records for each year 1991-2020.
Rain in April
Normal precipitation is 0.8 in; a dry April brings about 0.05 in and a wet one about 1.2 in (25th and 75th percentiles). About 1 day brings half an inch or more.
How April varies from year to year
- Warmest April, 1991-20202019: average high 80°F
- Coolest April1999: average high 68°F
- Wettest April2020: 3.5 in
- Driest April2008: no measurable precipitation
- Highest reading101°F (April 26, 2004)
- Lowest reading33°F (April 10, 1999)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
April compared with March and May
| March | April | May | |
|---|---|---|---|
| Normal high | 72°F | 76°F | 80°F |
| Normal low | 49°F | 51°F | 56°F |
| Wet days | 5 | 4 | 2 |
| Comfortable days | 17 | 16 | 16 |
| Daylight | 12.0 h | 13.1 h | 13.9 h |
Highs change by +4°F from March and +4°F into May.
Nearby alternatives in April
- Warmer: Palm Springs, CA65 mi · high 87°F · 1 wet day
- Cooler: Torrance, CA43 mi · high 68°F · 3 wet days
How Ontario ranks in April
- Normal high101st warmest of 378 cities; 10th of 60 in California
- Wet days40th driest of 378
- Comfortable days57th most of 340
What to pack for Ontario in April
- Layers – afternoons near 76°F but nights near 51°F
Heating and cooling
April has 105 heating degree days and 57 cooling degree days (base 65°F), 5% of the year's total heating and cooling demand.
Questions
How hot is Ontario in April?
The normal high is 76°F and the normal low is 51°F. From 1991 to 2020 the hottest April reading was 101°F (April 26, 2004).
Does it rain a lot in Ontario in April?
About 4 days in April have at least 0.01 in of precipitation, and the normal total is 0.8 in. The wettest April in 1991-2020 was in 2020 (3.5 in); the driest was in 2008, with no measurable precipitation.
Is April a good time to visit Ontario?
April ranks 2nd of 12 months on our comfort score for Ontario (73 out of 100). It has about 16 comfortable days and about 3 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.