Ontario, OR Weather & Climate Normals
What a normal year in Ontario actually looks like
On the 30-year record NOAA keeps for Ontario, OR, the comfort score comes out to 42/100, strongly seasonal: Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. Only 4 months a year land in the 55–75°F range this site treats as mild.
How much Ontario's weather actually swings
Average temperatures in Ontario run from 29°F in Jan up to 77°F in Jul, a 47.5°F seasonal swing, one of the widest gaps in this dataset.
Ontario, month by month
| Month | Avg high | Avg low | Precip |
|---|---|---|---|
| Jan | 36°F | 23°F | 1.3in |
| Feb | 44°F | 26°F | 0.79in |
| Mar | 56°F | 32°F | 1in |
| Apr | 63°F | 38°F | 0.87in |
| May | 74°F | 47°F | 1.41in |
| Jun | 82°F | 54°F | 0.68in |
| Jul | 93°F | 60°F | 0.25in |
| Aug | 91°F | 57°F | 0.1in |
| Sep | 81°F | 47°F | 0.34in |
| Oct | 65°F | 36°F | 0.77in |
| Nov | 47°F | 28°F | 0.9in |
| Dec | 36°F | 22°F | 1.58in |
If you're timing a visit, May, Jun, Aug, and Sep are Ontario's mildest stretch; if you're moving there, you should plan around Jul's heat and Jan's cold instead.
How wet Ontario actually gets
Ontario averages 9.99in of precipitation a year across roughly 70 days with measurable rain or snow; the nearest NOAA station does not record snowfall, so no snow figure is shown rather than guessed.
Ontario against the rest of the country
Out of 4876 cities scored here, Ontario comes in at 4242; within OR alone it ranks 80 of 80. Population is about 11,957.
Checking the actual forecast
These figures come from Ontario Ksrv, OR US, the NOAA station 1.3 miles from Ontario, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why some cities show no snow or rain figure · Why this uses the nearest NOAA station