An intense heat wave has settled in across Eastern Canada, prompting heat alerts all the way from Nova Scotia to Ontario.

The heat and humidity were particularly bad in those two provinces on Saturday, although temperatures also reached 30 C or higher in Quebec and New Brunswick.

In Halifax, which usually sees milder weather, people sweltered as the temperature climbed to 33 and felt like 40 because of the humidity.

Thick haze made the CN tower only partially visible from a distance.

Air quality advisories were issued for parts of the province.

In Ontario, the sweltering heat was accompanied by smog so heavy that the Environment Ministry issued an advisory for much of the southern part of the province.

The haze was so thick in Toronto that even the city's most famous landmark, the 553-metre-high CN Tower, was only partially visible from a distance.

The temperature in Toronto hit 34, which felt like 43 because of the humidity.

Among other hot spots, temperatures reached 31 in Montreal, 32 in Ottawa, and 34 in Fredericton.

Officials warned people – especially the young and the elderly – to try to stay inside in cool areas, protect themselves from the sun and drink lots of fluids.

Environment Canada officials have warned that there could be unusually high temperatures across the country for much of the summer.