OTTAWA -- A heat warning for Ottawa has returned, after a brief reprieve over the weekend.

Environment Canada says a period of hot weather will begin Tuesday.

"Daytime high temperatures in excess of 30 degrees Celsius, with humidex values in the high thirties to low forties, are expected this week. Overnight lows near 20 degrees Celsius are also expected through this period, providing little relief from the heat," the warning says. "A slightly cooler airmass may move into the area this weekend, however there is considerable uncertainty."

Heat warnings are also in effect for many parts of eastern Ontario, including areas to the south and east of the capital.

By 3 p.m. Monday, the temperature in Ottawa reached 30°C, with a humidex of 31.

A sun/cloud mix is in the outlook for Tuesday, with a high of 33°C and a humidex of 41.

High temperatures in the low 30s are expected to continue through the week, with overnight lows in the low 20s. There is a chance of showers later in the week.

Cooling centres opening

The City of Ottawa says it will be opening three emergency cooling centres for residents Tuesday and Wednesday to help with the heat wave.

  • Bernard-Grandmaître Arena, 309 McArthur Road
  • Ron Kolbus Lakeside Centre, 102 Greenview Avenue
  • Heron Road Community Centre, 1480 Heron Road

They will be open from 11 a.m. until 7 p.m. both days.

The centres will be set up to ensure users can practice proper physical distancing and will offer access to washrooms and drinking water. Residents are asked to bring a mask, as masks will be required inside spaces like community centres as of 12:01 a.m. Tuesday.

Staying cool during the heat wave

Ottawa Public Health offers tips to stay cool during the heat wave:

  •  Drink plenty of water and avoid alcohol and caffeine
  •  Avoid heavy outdoor activity
  •  Wear a hat, light and loose-fitting clothing, sunscreen and sunglasses when outside
  •  Bring an umbrella and water when you leave home
  •  Cool off in an air-conditioned space
  •  Cool off in the shade or at a park or greenspace
  •  Use a fan and mist your skin with water
  •  Take cool baths and showers as often as needed
  •  Keep your home cool by closing blinds and curtains on any windows facing the sun