Best time to visit Ontario
The best time to visit Ontario is October–June, judged on twenty years of weather records and the events worth going for.
Ontario, California, United States
°C
mm
- Average daily high and low
- Precipitation
- Good month
- Best month
- Made good or best by an event
| Month | Average daily high | Average daily low | Precipitation | Verdict |
|---|---|---|---|---|
| January | 17.7 °C / 64 °F | 7.2 °C / 45 °F | 72 mm / 2.8 in | best month |
| February | 18.1 °C / 65 °F | 7.6 °C / 46 °F | 76 mm / 3 in | best month |
| March | 19.1 °C / 66 °F | 8.9 °C / 48 °F | 60 mm / 2.3 in | best month |
| April | 21.4 °C / 71 °F | 10.7 °C / 51 °F | 23 mm / 0.9 in | best month |
| May | 22.9 °C / 73 °F | 12.9 °C / 55 °F | 10 mm / 0.4 in | best month |
| June | 26.7 °C / 80 °F | 15.7 °C / 60 °F | 1 mm / 0 in | best month |
| July | 29.9 °C / 86 °F | 18.5 °C / 65 °F | 2 mm / 0.1 in | good month |
| August | 30.7 °C / 87 °F | 18.9 °C / 66 °F | 5 mm / 0.2 in | good month |
| September | 29.4 °C / 85 °F | 17.8 °C / 64 °F | 7 mm / 0.3 in | good month |
| October | 25.8 °C / 78 °F | 14.1 °C / 57 °F | 14 mm / 0.6 in | best month |
| November | 21.7 °C / 71 °F | 10.3 °C / 51 °F | 30 mm / 1.2 in | best month |
| December | 17.4 °C / 63 °F | 7.2 °C / 45 °F | 75 mm / 3 in | best month |
Good and best months depend on more than temperature, rain and events. How they are chosen
Each activity on this page has its own good and best months, rated on twenty years of daily weather records. Which measures count, and how much, depends on the activity: humidity for exploring outdoors, wind for the beach, hiking and skiing, snow for skiing alone. Between them, the activities are rated on:
- Daytime highs
- Night-time lows
- How warm it feels
- Humidity
- How much of the day is sunny
- Hours of daylight
- Monthly rainfall
- How many days it rains
- Days of heavy rain
- Wind
- Snowfall and days with snow
- Major events, such as festivals
The chart shows the good and best months for exploring outdoors.
The event icon marks a month that an event lifts to good or best, such as a festival or a natural spectacle. Choose “Weather only” in the toolbar to rate the months on weather alone.
Best months by activity
Exploring outdoors
Mild days and nights, mostly dry and bright. The default for 'when should I go'.
- JJanuary: best
- FFebruary: best
- MMarch: best
- AApril: best
- MMay: best
- JJune: best
- JJuly: good
- AAugust: good
- SSeptember: good
- OOctober: best
- NNovember: best
- DDecember: best
- Best
- October–June
- Good
- July–September
Why these months
January · best
In its favour: feels like (high) 15.2 °C / 59 °F, share of daylight that is sunny 87%, average daily high 17.7 °C / 64 °F, precipitation 72 mm / 2.8 in, wet days 5.2 days, days with heavy rain 2.2 days, relative humidity 56%, average daily low 7.2 °C / 45 °F.
February · best
In its favour: feels like (high) 15.9 °C / 61 °F, average daily high 18.1 °C / 65 °F, share of daylight that is sunny 86%, precipitation 76 mm / 3 in, wet days 5.9 days, days with heavy rain 2 days, relative humidity 59%, average daily low 7.6 °C / 46 °F.
March · best
In its favour: feels like (high) 17.7 °C / 64 °F, average daily high 19.1 °C / 66 °F, precipitation 60 mm / 2.3 in, share of daylight that is sunny 90%, wet days 6.7 days, days with heavy rain 1.8 days, relative humidity 64%, average daily low 8.9 °C / 48 °F.
April · best
In its favour: feels like (high) 20.6 °C / 69 °F, average daily high 21.4 °C / 71 °F, precipitation 23 mm / 0.9 in, share of daylight that is sunny 89%, wet days 3.5 days, days with heavy rain 0.7 days, average daily low 10.7 °C / 51 °F, relative humidity 61%.
May · best
In its favour: feels like (high) 23 °C / 73 °F, average daily high 22.9 °C / 73 °F, precipitation 10 mm / 0.4 in, share of daylight that is sunny 92%, wet days 2.1 days, days with heavy rain 0.2 days, average daily low 12.9 °C / 55 °F, relative humidity 65%.
June · best
In its favour: feels like (high) 27.9 °C / 82 °F, precipitation 1 mm / 0 in, share of daylight that is sunny 95%, average daily high 26.7 °C / 80 °F, wet days 0.4 days, days with heavy rain 0 days, average daily low 15.7 °C / 60 °F, relative humidity 62%.
July · good
In its favour: precipitation 2 mm / 0.1 in, share of daylight that is sunny 97%, wet days 0.5 days, days with heavy rain 0.1 days, average daily low 18.5 °C / 65 °F, relative humidity 59%.
Against: feels like (high) 31.8 °C / 89 °F, average daily high 29.9 °C / 86 °F.
August · good
In its favour: precipitation 5 mm / 0.2 in, share of daylight that is sunny 96%, wet days 0.3 days, days with heavy rain 0.1 days, average daily low 18.9 °C / 66 °F, relative humidity 57%.
Against: feels like (high) 32.4 °C / 90 °F, average daily high 30.7 °C / 87 °F.
September · good
In its favour: precipitation 7 mm / 0.3 in, share of daylight that is sunny 94%, feels like (high) 30.2 °C / 86 °F, wet days 1.4 days, days with heavy rain 0.2 days, average daily high 29.4 °C / 85 °F, average daily low 17.8 °C / 64 °F, relative humidity 57%.
October · best
In its favour: feels like (high) 24.7 °C / 76 °F, average daily high 25.8 °C / 78 °F, precipitation 14 mm / 0.6 in, share of daylight that is sunny 93%, wet days 2.6 days, days with heavy rain 0.4 days, average daily low 14.1 °C / 57 °F, relative humidity 53%.
November · best
In its favour: feels like (high) 19.2 °C / 67 °F, average daily high 21.7 °C / 71 °F, precipitation 30 mm / 1.2 in, share of daylight that is sunny 91%, wet days 3.3 days, days with heavy rain 1 days, average daily low 10.3 °C / 51 °F, relative humidity 50%.
December · best
In its favour: feels like (high) 14.9 °C / 59 °F, share of daylight that is sunny 84%, average daily high 17.4 °C / 63 °F, precipitation 75 mm / 3 in, wet days 5.5 days, days with heavy rain 2.1 days, relative humidity 57%, average daily low 7.2 °C / 45 °F.
An activity is listed only where it applies: skiing at ski destinations, beach and swimming at beach destinations. The nearest ski area is Mt. Baldy, 24 km away.
Weather averages
Monthly averages over twenty years, 2006–2025. Highs, lows and precipitation are in the chart at the top.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels like (high) | 15.2 °C | 15.9 °C | 17.7 °C | 20.6 °C | 23 °C | 27.9 °C | 31.8 °C | 32.4 °C | 30.2 °C | 24.7 °C | 19.2 °C | 14.9 °C |
| Days with heavy rain | 2.2 days | 2 days | 1.8 days | 0.7 days | 0.2 days | 0 days | 0.1 days | 0.1 days | 0.2 days | 0.4 days | 1 days | 2.1 days |
| Time rain usually falls | 3 pm | 5 pm | 2 pm | 4 pm | 4 pm | 12 pm | 12 pm | 2 pm | 2 pm | 1 pm | 11 am | 2 pm |
| Sunshine per day | 8.9 h | 9.4 h | 10.8 h | 11.7 h | 12.8 h | 13.7 h | 13.7 h | 12.9 h | 11.7 h | 10.5 h | 9.4 h | 8.4 h |
| Relative humidity | 56% | 59% | 64% | 61% | 65% | 62% | 59% | 57% | 57% | 53% | 50% | 57% |
Air quality
Averaged over a shorter period (2022–2025) than the twenty-year averages above, and not counted towards good or best months.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Air pollution (PM2.5) 2022–2025 | 12.7 µg/m³ | 14.2 µg/m³ | 15.2 µg/m³ | 20.2 µg/m³ | 16.7 µg/m³ | 18 µg/m³ | 23.1 µg/m³ | 22.5 µg/m³ | 20.8 µg/m³ | 19.3 µg/m³ | 13.7 µg/m³ | 15.4 µg/m³ |
| Air pollution (PM2.5, daily peak) 2022–2025 | 24.4 µg/m³ | 27.4 µg/m³ | 26.9 µg/m³ | 31.7 µg/m³ | 23.3 µg/m³ | 24.4 µg/m³ | 29.4 µg/m³ | 31.5 µg/m³ | 32.4 µg/m³ | 33 µg/m³ | 26 µg/m³ | 29.6 µg/m³ |
- Good 15 µg/m³ or less
- Fair 15 to 25 µg/m³
- Moderate 25 to 37.5 µg/m³
- Poor 37.5 to 50 µg/m³
- Very poor 50 to 75 µg/m³
- Extremely poor over 75 µg/m³
Each figure is compared with the World Health Organization's guideline for a day's air, 15 µg/m³ or less, and with its interim targets above that. The words are ours: the WHO does not name its steps. The figures are modelled monthly averages, so single days can be well above them. The daily peak is the average of each day's highest hour, shaded on the same scale.