The temperatures in Sarnia in July are comfortable with low of 18°C and and high up to 26°C.
You can expect about 3 to 8 days of rain in Sarnia during the month of July. 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 July 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
26° / 18°
Rainy Days
7
Snowy Days
0
Dry Days
24
Rainfall
30
mm
Sun Hours
2.6
Hrs
