St. Thomas, Ontario, can expect a stretch of sunny skies and steadily rising temperatures as the first full week of June unfolds. Environment Canada is calling for mainly clear conditions through the work week, with daytime highs climbing from the low 20s into the mid-20s, making it feel more like summer.
Monday will be mainly sunny with a high of 20°C, followed by a string of sunny days on Tuesday, Wednesday, and Thursday, each reaching 24°C. Friday will bring a mix of sun and clouds and a high of 26°C. Overnight lows will remain comfortably mild, starting at 9°C Monday night and gradually warming to 18°C by Friday night.
With the sunshine comes a strong June sun. Environment Canada warns that the UV index in southern Ontario often reaches 6 to 10 this time of year, meaning very high levels are possible. Residents spending time outside are reminded to wear sunscreen, hats, and seek shade, especially between 11 a.m. and 3 p.m. when the sun is at its strongest.
A shift toward more unsettled weather is expected by Friday night into the weekend. A weather system is forecast to bring increasing cloud cover, a 40 percent chance of showers Saturday morning, and likely showers by Sunday with about 5 mm of rain possible. This pattern lines up with typical June weather in Southwestern Ontario, where an average of 80 to 100 mm of rain falls over nine or ten days in the month.
Overall, the forecast is right in line with seasonal norms for early June in St. Thomas. Average highs generally rise from 21°C at the start of the month to around 27°C by month’s end, with overnight lows typically between 10°C and 16°C. After a pleasant and sunny work week, residents will want to keep an umbrella handy as the weekend approaches.
