Environment Canada has issued a heat warning for the city of Toronto as temperatures are set to climb to 35°C on Thursday.

The federal weather agency issued the heat warning as a prolonged period of hot weather is expected this afternoon through Sunday, with high temperatures likely to persist into next week.

READ: Where to Find the City’s 14 Cooling Centres in Toronto (MAP)

According to Environment Canada, on Thursday, temperatures are expected to sit between 32°C and 35°C, which will feel more like 35°C to 38°C with the humidex.

On Friday, temperatures are forecast to sit between 32°C and 34°C, which will feel more like 36°C and 40°C with the humidex, while Saturday will see maximum temperatures of between 32°C and 35°C, or 36°C to 40°C with the humidex. On Sunday, temperatures are forecast to reach a high of 35°C, or 42°C with the humidex.

Minimum overnight temperatures are forecast to sit between 20°C and 23°C.

Environment Canada says the high temperatures are expected in portions of southwestern Ontario, the Golden Horseshoe, and portions of Eastern Ontario.

Hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index to approach the high risk category.

The weather agency is advising the public that extreme heat affects everyone and that the risks are greater for young children, pregnant women, older adults, people with chronic illnesses, and people working or exercising outdoors.

Environment Canada also says to never leave people or pets inside a parked vehicle during this time.

The public should also watch for the symptoms of heat illness, which includes dizziness, fainting, nausea/vomiting, rapid breathing and heartbeat, extreme thirst, and decreased urination with unusually dark urine.

To ensure that all residents have access to a cool space during this time, the City will be opening 15 emergency cooling centres throughout the city. The cooling centres will open to the public on Thursday at 11 am.