Hamilton, much of southern Ontario in for another heat wave, says Environment Canada

Just a week after the last heat wave, Hamilton, Niagara and much of southern and southwestern Ontario are under another warning.

As of Friday afternoon, Environment Canada is forecasting highs of 31 C to 33 C this weekend, with humidity making it feel like 40 C.

The high heat is forecasted to start Saturday and end Sunday night. Overnight lows will be 21 C to 25 C, "providing little relief from the heat," the federal weather agency said on its website.

Hamilton's medical officer of health Elizabeth Richardson issued a statement Friday noting the city and community agencies will open cool areas for people to go. Regularly scheduled public swims at indoor pools will be free of charge. 

To reduce the risk of heat-related illness, Richardson recommends people:

• Drink plenty of water, avoiding alcoholic and caffeinated beverages. 
• Go to an air-conditioned place. 
• Wear light, loose-fitting clothing. Wear sunscreen and a hat, or take an umbrella.
• Limit physical activities during the day. 
• Take a cool bath or shower.
• Close your blinds or curtains. Open windows to let air circulate when using a fan.
• Never leave children or pets alone in closed vehicles. 
• Check on your neighbours and family.

Signs and symptoms of heat exhaustion include heavy sweating, weakness, cold, pale and clammy skin, a weak pulse, fainting and vomiting, Hamilton public health says, adding anyone experiencing symptoms should seek help right away. 

CBC's Climate Dashboard says over the next few days, the maximum temperature in Hamilton will be 33 C, which is 7 C above average when compared to data from 1981 to 2010. The minimum temperature will be 16 C, which is 2 C above average.

The dashboard predicts that if current fossil-fuel-emissions trends continue, the average annual temperature is likely to increase by 2.6 C to 4.8 C in Hamilton by the end of the century.