Click on a day for an hourly weather forecast
The temperatures in Sarnia in October are quite cold with temperatures between 8°C and 15°C, warm clothes are a must.
You can expect rain for roughly half of the month of October in Sarnia. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Sarnia in October 2025.
If you’re planning to visit Sarnia in the near future, we highly recommend that you review the 14 day weather forecast for Sarnia before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -7° | 11 | 17 | 3 | 22 mm | Awful | Sarnia in January |
| February | -1° / -7° | 8 | 15 | 5 | 23 mm | Awful | Sarnia in February |
| March | 5° / -3° | 7 | 21 | 3 | 27 mm | Awful | Sarnia in March |
| April | 11° / 3° | 8 | 21 | 1 | 39 mm | Ok | Sarnia in April |
| May | 18° / 9° | 7 | 24 | 0 | 36 mm | Good | Sarnia in May |
| June | 23° / 14° | 7 | 23 | 0 | 38 mm | Perfect | Sarnia in June |
| July | 26° / 18° | 7 | 24 | 0 | 30 mm | Perfect | Sarnia in July |
| August | 25° / 17° | 6 | 25 | 0 | 29 mm | Perfect | Sarnia in August |
| September | 22° / 14° | 6 | 24 | 0 | 29 mm | Good | Sarnia in September |
| October | 15° / 8° | 8 | 24 | 0 | 39 mm | Good | Sarnia in October |
| November | 8° / 2° | 8 | 22 | 1 | 26 mm | Ok | Sarnia in November |
| December | 2° / -3° | 9 | 19 | 3 | 24 mm | Awful | Sarnia in December |