Guelph, Ontario is enjoying clear skies and hot temperatures this Wednesday, August 5, 2026, but showers are expected to return Thursday and persist on and off through the weekend. Environment Canada reports no active weather alerts for the city, with Wednesday’s high reaching near 29 degrees Celsius and a Humidex making it feel more like 34.
The UV index is forecast to be very high at 9, meaning residents should take extra care in the sun. According to Environment Canada, UV levels of 8 or more mean you should limit sun exposure, especially between 11 a.m. and 3 p.m. Hats, sunscreen, and shade are all smart choices if you are out enjoying the heat.
At 4:00 p.m., the temperature at the Guelph Turfgrass Institute station sat at 27.6 degrees, with a Humidex reading of 30. The Humidex scale shows that readings between 30 and 39 cause some discomfort, and outdoor exercise should be eased or moved to a cooler time.
Things shift Thursday. The forecast calls for mainly cloudy skies, a 40 percent chance of showers, and a risk of a thunderstorm. The high will again be near 27 degrees, but the Humidex could hit 35, and the UV index will be 7, which is still considered high. Showers stay in the picture Friday, Saturday, and Monday, with the best odds of rain (60 percent) coming Saturday and Monday, when highs will dip to the mid-20s.
This changeable pattern fits the Ontario summer outlook from The Weather Network, which flagged a season of heat building at times but frequent interruptions from showers and thunderstorms. The first half of August is expected to bring above-normal warmth to Eastern Canada before a possible shift later in the month.
