Ontario, CA weather in January
In January, Ontario sees highs around 68°F and lows around 45°F: mild and mostly dry. There are about 5 days with rain. It is one of the coolest months in Ontario. Good for outdoor plans.
- Normal high
- 68°F
- Normal low
- 45°F
- Wet days
- 5
- 2.6 in total
- Muggy days
- 0
- dew point 65°F+
How January changes from start to finish
| January 1 | January 31 | |
|---|---|---|
| Normal high | 67°F | 68°F |
| Normal low | 44°F | 45°F |
| Chance of a wet day | 17% | 18% |
| Sunrise / sunset | 6:56 am / 4:52 pm | 6:48 am / 5:19 pm |
| Daylight | 9.9 h | 10.5 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 January day
- 6 am43°Fdew point 34°F
- 9 am51°Fdew point 36°F
- Noon63°Fdew point 34°F
- 3 pm65°Fdew point 33°F
- 6 pm56°Fdew point 36°F
- 9 pm50°Fdew point 36°F
NOAA hourly normals (local standard time) from March AFB (26 mi away); average wind 5 mph; clear or few clouds in 58% of daytime hours, mostly cloudy or overcast in 35%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F16 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow5 of 31
- Notable rainat least 0.10 in3 of 31
- Freezing nightslow 32°F or below1 of 31
Average days per January, counted from daily records for each year 1991-2020.
Rain in January
Normal precipitation is 2.6 in; a dry January brings about 0.7 in and a wet one about 3.1 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more. Snow is very rare.
How January varies from year to year
- Warmest January, 1991-20202014: average high 76°F
- Coolest January2017: average high 61°F
- Wettest January2005: 8.2 in
- Driest January2003: no measurable precipitation
- Highest reading90°F (January 31, 2003)
- Lowest reading25°F (January 14, 2007)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
January compared with December and February
| December | January | February | |
|---|---|---|---|
| Normal high | 67°F | 68°F | 68°F |
| Normal low | 44°F | 45°F | 46°F |
| Wet days | 6 | 5 | 6 |
| Comfortable days | 15 | 16 | 13 |
| Daylight | 9.9 h | 10.2 h | 11.0 h |
Highs change by +1°F from December and 0°F into February.
Nearby alternatives in January
- Cooler: Victorville, CA39 mi · high 58°F · 5 wet days
How Ontario ranks in January
- Normal high45th warmest of 378 cities; 15th of 60 in California
- Wet days41st driest of 378
- Comfortable days30th most of 339
Heating and cooling
January has 280 heating degree days and 5 cooling degree days (base 65°F), 9% of the year's total heating and cooling demand.
Questions
How cold is Ontario in January?
The normal high is 68°F and the normal low is 45°F. From 1991 to 2020 the coldest January reading was 25°F (January 14, 2007).
Does it rain a lot in Ontario in January?
About 5 days in January have at least 0.01 in of precipitation, and the normal total is 2.6 in. The wettest January in 1991-2020 was in 2005 (8.2 in); the driest was in 2003, with no measurable precipitation.
Is January a good time to visit Ontario?
January ranks 5th of 12 months on our comfort score for Ontario (66 out of 100). It has about 16 comfortable days. 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.