Grimsby, Ontario is in for a warm and unsettled start to the week, with a chance of showers and thunderstorms Monday before temperatures climb toward a sunny 29°C by Wednesday. Environment Canada’s latest forecast shows no weather alerts currently in effect for the area, but residents planning outdoor activities should keep an eye on changing conditions.
As of Monday afternoon, the Vineland Station observation site reported a temperature of 20.3°C with 91 percent humidity, making it feel like 27 with the humidex. Monday’s high is expected to reach 25°C, but the humidex will push up to 33. There is a 60 percent chance of showers and a risk of a thunderstorm.
Tuesday will see clearing skies with a mix of sun and cloud, a high of 25°C, and a humidex of 32. The UV index is forecast to hit 9, which is considered very high. Health Canada recommends avoiding long periods in the sun between 11 a.m. and 3 p.m., wearing UV protection sunglasses, staying in shade, and reapplying sunscreen every two hours when the UV index is 8 or more.
Wednesday is shaping up to be the hottest day of the week, with sunny skies and a high of 29°C. The chance of showers returns Thursday and Friday before conditions clear up again by the weekend. The area was under an Orange Level Heat Warning earlier this month, from June 30 to early July, when temperatures soared to between 31 and 37°C on July 1 and 2. That warning has since ended, and no alerts are currently active for the St. Catharines-Grimsby-Northern Niagara Region.
Environment Canada issues heat warnings when air temperature or humidex forecasts reach levels that could affect health, typically giving 18 to 24 hours of advance notice. Thresholds for warnings vary by location. The heat warning criteria help local authorities, like the Town of Grimsby and Niagara Region Public Health, coordinate responses such as opening cooling spaces.
