Sarnia, Ontario, is in for a hot and sunny start to the week before thunderstorms bring a chance of rain and a drop in temperatures later on. Environment Canada forecasts highs of 28 degrees Celsius on Monday, though it will feel more like 31 with the humidity. The UV index is 9, or very high, meaning anyone outside should take extra care in the sun.
The high UV rating is a reminder to limit time in the sun, especially between 11 a.m. and 3 p.m., and to reapply sunscreen every two hours, according to Environment Canada’s sun safety guidelines. The same guidelines note southern Ontario often records the country’s highest UV numbers, and the index itself was created by Environment Canada scientists in Toronto in 1992 before global adoption.
Overnight Monday into Tuesday, conditions will shift. There is a 30 percent chance of showers after midnight with a risk of thunderstorms, continuing into Tuesday with a 40 percent chance of rain. Tuesday’s high of 29 degrees will feel like 37 with the humidex, so those sensitive to heat may want to plan indoor activities. The unsettled weather could bring needed rain to the area, but it also comes with lightning risks.
Environment Canada’s lightning safety page warns that if you can hear thunder, you are within striking distance, and you should wait at least 30 minutes after the last rumble before heading back outside. Each year, lightning kills two to three Canadians and injures about 180.
The heat will stick around through mid-week. Wednesday and Thursday are both expected to hit 31 degrees, well above the normal June high of 24. A gradual cooldown is forecast into the weekend, with Sunday reaching 24 degrees. Residents should keep an eye on the forecast, as daily shower chances continue throughout the week.
