Climate averages 1991–2020
Sarnia weather
in October.
A cool, moderately wet month: the 6th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
October is a cool month in Sarnia: daytime highs average 14.7°C and nights cool to about 8.5°C. By daytime temperature it is the 6th warmest of the 12 months.
Expect about 76 mm of rain on roughly 11 days, which makes October a moderately wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 05 min on an average October day.
The nearest other city in this atlas is Clinton Township (61 km away). In October its highs average 15.0°C, about as warm as Sarnia, with 68 mm of rain.
Among the 86 cities listed in Canada, Sarnia ranks 3rd of 86 for the warmest October highs and joint 21st of 86 for the driest October (rainfall, lowest first). The mean October high of those 86 cities is 12.7°C; Sarnia is 2.1°C warmer than that mean.
From October to November, average highs fall by 7.1°C to 7.7°C, and monthly rainfall falls from 76 mm to 66 mm.
The annual picture
October in context
Monthly precipitation
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
Sarnia climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -1.2°C-7.8°C | -7.8°C | 57 | 9.6 | 9.49 h |
| February | -0.3°C-8.0°C | -8.0°C | 52 | 8.4 | 10.510 h |
| March | 4.6°C-3.7°C | -3.7°C | 57 | 9.6 | 11.912 h |
| April | 11.4°C2.8°C | 2.8°C | 85 | 11.4 | 13.413 h |
| May | 18.3°C9.7°C | 9.7°C | 85 | 12.0 | 14.615 h |
| June | 23.7°C15.9°C | 15.9°C | 87 | 10.7 | 15.315 h |
| July | 26.1°C18.8°C | 18.8°C | 71 | 11.0 | 15.015 h |
| August | 25.2°C18.3°C | 18.3°C | 70 | 10.4 | 13.914 h |
| September | 21.7°C14.7°C | 14.7°C | 73 | 9.1 | 12.513 h |
| October, selected | 14.7°C8.5°C | 8.5°C | 76 | 10.8 | 11.111 h |
| November | 7.7°C2.2°C | 2.2°C | 66 | 9.7 | 9.810 h |
| December | 1.8°C-3.3°C | -3.3°C | 56 | 9.4 | 9.19 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet 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
- Clinton Township in OctoberUnited States · 61 kmHigh 15.0°C · Low 8.4°C · 68 mm rain
- Shelby in OctoberUnited States · 62 kmHigh 15.1°C · Low 8.0°C · 72 mm rain
- Sterling Heights in OctoberUnited States · 68 kmHigh 15.2°C · Low 8.3°C · 68 mm rain
- Rochester Hills in OctoberUnited States · 70 kmHigh 15.0°C · Low 7.7°C · 75 mm rain
- Warren in OctoberUnited States · 74 kmHigh 15.3°C · Low 7.9°C · 68 mm rain
- Troy in OctoberUnited States · 74 kmHigh 15.1°C · Low 7.9°C · 71 mm rain
- Southfield in OctoberUnited States · 87 kmHigh 15.3°C · Low 7.9°C · 71 mm rain
- Waterford in OctoberUnited States · 88 kmHigh 14.9°C · Low 7.4°C · 75 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 Sarnia) is explained once on the Sarnia year overview and on the Sources, method and limits page.