UV Index
UV Index
Today's UV index in Sarnia, Canada 
will be up to 9.4, indicating a very high level of sun exposure for the average person. Check our tips for today to make sure you're safe in the sun.
Last checked: 2025-06-24
With a UV index of 9.4 in Sarnia, it's crucial to safeguard your skin from harmful UV rays. Protect yourself by minimizing sun exposure, wearing protective clothing, and applying SPF 30+ sunscreen every 2 hours.
Sarnia, Canada, usually has a UV index ranging from low to moderate levels, with higher values in the summer months when the sun is stronger. Winter months tend to have very low UV index values.
The weather in Sarnia changes with the seasons. Winters are cold and snowy, while summers are warm and sometimes humid. Spring and fall bring mild temperatures and varying rainfall, making the climate pretty different throughout the year.
Compared to other areas in southwestern Ontario, Sarnia experiences similar weather, with cold winters and warm summers. It is generally cooler than places further south in the U.S. but milder than northern parts of Canada due to its location near Lake Huron.
See the UV index hour by hour for Sarnia, along with the temperature and how cloudy it is. If the UV level is higher than moderate, it's best to avoid direct sunlight.