Cornwall, Ontario is in for a hot and sunny start to the week, with Environment Canada forecasting very high UV levels and temperatures well above normal. On Monday, June 8, the UV index is expected to hit 9, a level considered very high, while Tuesday’s high will climb to 30°C with a Humidex of 33 — about 7 degrees above the seasonal norm of 23°C.
According to Environment Canada, a UV index of 9 means unprotected skin can burn quickly on clear, sunny days. The agency advises residents to use sunscreen with SPF 30 or higher, stay in the shade during peak sun hours between 11 a.m. and 3 p.m., and wear UV-protective sunglasses.
The heat on Tuesday will feel even more intense due to humidity, with the Humidex making it seem like 33°C. While these temperatures do not trigger an official heat warning — which requires extreme conditions for two or more days — they still pose health risks. Health Canada warns that heat illnesses, including heat rash, heat cramps, heat exhaustion, and heat stroke, can develop quickly and lead to serious long-term problems.
Those most at risk include older adults, infants and young children, people with chronic illnesses, and anyone working or exercising outdoors. Even indoor temperatures can be dangerous during these conditions, and officials remind everyone to drink plenty of water and check on vulnerable neighbours.
Relief is expected by mid-week, when cloud cover and a 60% chance of showers will bring temperatures back down to around 24°C. However, the forecast shows more heat returning by Friday, with another high of 31°C. Environment Canada continues to monitor conditions and urges Cornwall residents to take sun safety seriously, especially as southern Ontario often records Canada’s highest UV index values.
