The temperatures in Sarnia in May are quite cold with temperatures between 9°C and 18°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Sarnia during the month of May. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Sarnia in May 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.
Temperatures
18° / 9°
Rainy Days
7
Snowy Days
0
Dry Days
24
Rainfall
36
mm
Sun Hours
2.0
Hrs
