Climate averages 1991–2020
Ontario weather
in October.
A warm, fairly dry month: the 5th warmest and the 6th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
October is a warm month in Ontario: daytime highs average 26.5°C and nights cool to about 13.8°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 19 mm of rain on roughly 3 days, which makes October a fairly dry month (the 6th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 22 min on an average October day.
The nearest other city in this atlas is Chino (7 km away). In October its highs average 26.1°C, about as warm as Ontario, with 19 mm of rain.
Among the 498 cities listed in the United States, Ontario ranks joint 76th of 498 for the warmest October highs and joint 61st of 498 for the driest October (rainfall, lowest first). The mean October high of those 498 cities is 21.4°C; Ontario is 5.1°C warmer than that mean.
From October to November, average highs fall by 4.9°C to 21.6°C, and monthly rainfall rises from 19 mm to 25 mm.
The annual picture
October in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Ontario climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 17.5°C6.4°C | 6.4°C | 93 | 5.9 | 10.210 h |
| February | 17.8°C6.7°C | 6.7°C | 102 | 6.6 | 10.911 h |
| March | 19.7°C8.2°C | 8.2°C | 62 | 6.2 | 12.012 h |
| April | 22.1°C9.8°C | 9.8°C | 25 | 3.7 | 13.013 h |
| May | 24.6°C12.4°C | 12.4°C | 11 | 2.2 | 13.914 h |
| June | 28.4°C15.3°C | 15.3°C | 2.4 | 0.3 | 14.414 h |
| July | 31.8°C18.6°C | 18.6°C | 1.7 | 0.5 | 14.214 h |
| August | 32.8°C19.3°C | 19.3°C | 0.9 | 0.2 | 13.413 h |
| September | 31.1°C17.7°C | 17.7°C | 4.3 | 0.9 | 12.412 h |
| October, selected | 26.5°C13.8°C | 13.8°C | 19 | 2.6 | 11.411 h |
| November | 21.6°C9.5°C | 9.5°C | 25 | 2.8 | 10.410 h |
| December | 17.2°C6.1°C | 6.1°C | 62 | 5.3 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
October in nearby cities
- Chino in OctoberUnited States · 7 kmHigh 26.1°C · Low 13.3°C · 19 mm rain
- Rancho Cucamonga in OctoberUnited States · 7 kmHigh 26.4°C · Low 13.2°C · 22 mm rain
- Pomona in OctoberUnited States · 9 kmHigh 26.3°C · Low 13.7°C · 19 mm rain
- Chino Hills in OctoberUnited States · 13 kmHigh 25.6°C · Low 13.2°C · 19 mm rain
- Fontana in OctoberUnited States · 20 kmHigh 26.3°C · Low 12.2°C · 22 mm rain
- Corona in OctoberUnited States · 22 kmHigh 27.0°C · Low 13.7°C · 22 mm rain
- Riverside in OctoberUnited States · 26 kmHigh 26.9°C · Low 12.7°C · 22 mm rain
- West Covina in OctoberUnited States · 27 kmHigh 27.2°C · Low 14.0°C · 16 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Ontario) is explained once on the Ontario year overview and on the Sources, method and limits page.
Pomona, Chino and Chino Hills lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.