Ontario weather in October
In October, Ontario has daytime highs averaging 27 °C, nights around 14 °C, with 2.6 wet days. Figures are 1991–2020 climate normals.
- 27.0°C Average high
- 14.0°C Average low
- 2.6days Wet days
- 19mm Rainfall
- 11h Daylight
Daily temperatures through October
How October develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 October | 28.7 °C | 15.2 °C | 8 % |
| 11–20 October | 27.4 °C | 14.2 °C | 9 % |
| 21–31 October | 25.5 °C | 12.9 °C | 8 % |
- Average highs fall from 28.7 °C early in October to 25.5 °C by the end of it.
What to expect
| Measure | Typical October | Share of the month |
|---|---|---|
| Days above 25 °C | 20 of 31 | 65 % |
| Days above 30 °C | 9.0 of 31 | 29 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 2.6 of 31 | 8 % |
Conditions in October
| Measure | Average |
|---|---|
| Mean temperature | 20 °C |
| Record high (1991–2020) | 40 °C |
| Record low (1991–2020) | 5.5 °C |
| Relative humidity | 54 % |
| Wind speed | 11 km/h |
| Cloud cover | 26 % |
Where Ontario ranks in October
| Ranking | Position | Value |
|---|---|---|
| The driest places in North America in October | 27thof 50 | 19 mm |
October compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| August | 33.1 °C | 1 mm | 13 % |
| September | 31.6 °C | 5 mm | 17 % |
| October | 27.0 °C | 19 mm | 26 % |
| November | 22.1 °C | 27 mm | 35 % |
| December | 17.7 °C | 64 mm | 43 % |
See all twelve months for Ontario
- October is the 5th warmest month here.
- It is the 6th driest month of the year.
- It ranks 5th for least cloud cover.
- Days last about 11 hours from sunrise to sunset.
- It rains on 2.6 of 31 days — 8 % of the month.
- Nights are about 13 °C cooler than the middle of the day.
- The hottest October day on record since 1991 reached 40 °C, 13 °C above the usual daytime high.
Nearby destinations in October
| Destination | Avg high | Wet days | Sea |
|---|---|---|---|
| Ontario | 27 °C | 2.6 | – |
| Pomona | 27 °C | 3 | – |
| Fontana | 27 °C | 3 | – |
| Corona | 28 °C | 3 | – |
| Riverside | 28 °C | 3 | – |
| San Bernardino | 27 °C | 3 | – |
| Anaheim | 26 °C | 2 | 19 |
QuestionsOctober in Ontario, answered
How warm is Ontario in October?
Daily highs average 27 °C and nights fall to about 14 °C, a spread of 13 °C between afternoon and dawn. That makes October the 5th warmest month of the year here.
Does it rain much in Ontario in October?
October averages 19 mm of rain, spread over about 3 of the 31 days — 8 % of the month. Cloud cover averages 26 % of the sky.
How long are the days in October?
Ontario averages 11 hours between sunrise and sunset in October. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.