Ontario, CA weather in October
October in Ontario: warm and dry. Highs 83°F, lows 57°F, rain on about 2 days. A good month for most outdoor plans.
- Normal high
- 83°F
- Normal low
- 57°F
- Wet days
- 2
- 0.4 in total
- Muggy days
- 0
- dew point 65°F+
How October changes from start to finish
| October 1 | October 31 | |
|---|---|---|
| Normal high | 86°F | 80°F |
| Normal low | 61°F | 53°F |
| Chance of a wet day | 4% | 9% |
| Sunrise / sunset | 6:45 am / 6:35 pm | 7:09 am / 5:58 pm |
| Daylight | 11.8 h | 10.8 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 October day
- 6 am53°Fdew point 44°F
- 9 am68°Fdew point 45°F
- Noon80°Fdew point 40°F
- 3 pm80°Fdew point 41°F
- 6 pm69°Fdew point 45°F
- 9 pm62°Fdew point 47°F
NOAA hourly normals (local standard time) from March AFB (26 mi away); average wind 5 mph; clear or few clouds in 72% of daytime hours, mostly cloudy or overcast in 21%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F12 of 31
- Hot dayshigh 90°F or more8 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow2 of 31
- Notable rainat least 0.10 in1 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per October, counted from daily records for each year 1991-2020.
Rain in October
Normal precipitation is 0.4 in; a dry October brings about 0.01 in and a wet one about 0.6 in (25th and 75th percentiles). Days with half an inch or more are rare.
How October varies from year to year
- Warmest October, 1991-20201999: average high 89°F
- Coolest October2000: average high 74°F
- Wettest October2004: 3.6 in
- Driest October1999: no measurable precipitation
- Highest reading107°F (October 1, 2012)
- Lowest reading41°F (October 31, 2019)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
October compared with September and November
| September | October | November | |
|---|---|---|---|
| Normal high | 91°F | 83°F | 75°F |
| Normal low | 64°F | 57°F | 49°F |
| Wet days | 1 | 2 | 4 |
| Comfortable days | 4 | 12 | 18 |
| Daylight | 12.4 h | 11.3 h | 10.4 h |
Highs change by -8°F from September and -8°F into November.
Nearby alternatives in October
- Warmer: Palm Springs, CA65 mi · high 91°F · 1 wet day
- Cooler: Torrance, CA43 mi · high 74°F · 2 wet days
How Ontario ranks in October
- Normal high50th warmest of 378 cities; 11th of 60 in California
- Wet days29th driest of 378
- Comfortable days176th most of 340
What to pack for Ontario in October
- Layers – afternoons near 83°F but nights near 57°F
Heating and cooling
October has 26 heating degree days and 177 cooling degree days (base 65°F), 6% of the year's total heating and cooling demand.
Questions
How hot is Ontario in October?
The normal high is 83°F and the normal low is 57°F. From 1991 to 2020 the hottest October reading was 107°F (October 1, 2012).
Does it rain a lot in Ontario in October?
About 2 days in October have at least 0.01 in of precipitation, and the normal total is 0.4 in. The wettest October in 1991-2020 was in 2004 (3.6 in); the driest was in 1999, with no measurable precipitation.
Is October a good time to visit Ontario?
October ranks 9th of 12 months on our comfort score for Ontario (60 out of 100). It has about 12 comfortable days and about 8 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.