https://en.wikipedia.org/wiki/Geography_of_Toronto#Climate
Toronto's continental climate is moderated by Lake Ontario; its climate is among the mildest in Canada east of the Rocky Mountains, given Toronto's latitude. Downtown Toronto sits in a pocket of the humid continental climate (Köppen climate classification Dfa) zone found at the southwestern end of Lake Ontario covering the southern part of the city — including downtown (but excluding the Toronto Islands), where the annual average temperature exceeds 9 °C (48 °F). Much of the rest of Toronto outside of the former city limits is in Dfb. It is located in hardiness zone 7a.[2] There is a high degree of variability from year to year and sometimes even over a period of days, particularly during the winter months.
Lake Ontario's water temperature varies due to upwelling of colder water or warmer pools of surface water creating very localized thermal contrast; the deeper waters of the lake, far from the shore, remain at a near constant water temperature of 4 °C (39 °F), the effect of which is either cooling or warming (in winter). This creates generally warmer nights through the colder season. When offshore winds occur in summer, they warm as they blow toward the lakeshore in the evening; conversely, the cooling effect by the lake is most pronounced on spring afternoons, which affects Toronto even more than other cities on the Great Lakes as during spring onshore east to southeast winds are predominant, on some days, the temperatures can be as much as 10 °C (18 °F) cooler than areas located far enough away from the Lake Ontario, an effect that wanes by summer when the dominant windflow becomes more southwesterly.
Springs and autumns are briefer than summers and winters, and feature varied weather with alternating periods of dry, sunny weather and rain. Many days in these seasons are sunny with pleasant rather than warm or cold temperatures. Nights are generally cool, but frosts are rare. Snow can fall in early spring or late fall but usually melts quickly after contact with the ground. At these changeable times of the year, temperature contrasts (up to 30 °C (54 °F) in extreme cases) can occur within a short period due to rapidly changing air masses that sweep across the continent. Toronto's weather is affected by the relative position of the polar jet stream and storm track, both of which pass over the area with some frequency.
Annual average precipitation is 831 mm (32.72 in).
Summer
Maximum temperatures typically range from 23 to 31 °C (73 to 88 °F) with moderate to high humidity, proximity to Lake Ontario and the other lakes contribute to summer moisture content but far away sources like the Gulf of Mexico also factor in. Temperatures over 32 °C (90 °F) occur but usually no longer than over a period of a few days and they very rarely exceed 38 °C (100 °F). Night temperatures generally hover close to 20 °C (68 °F) in the city but during hotter spells can remain closer to 25 °C (77 °F). Summer heat episodes are usually broken by cooler, drier periods not experienced further south on the continent. But intense heat episodes pose a health risk to some as they often arrive with high humidity and dangerous levels of airborne smog. Summer thunderstorms are a regular occurrence and can pop up quickly, especially west and north of the city in areas more prone to the "lake breeze front" or "lake breeze thunderstorms" phenomenon, in which intense, sharply defined squall lines develop quickly on summer afternoons amplified by localized wind patterns between the Great Lakes.[10] These storms sometimes move into the city causing localized flooding, intense lightning and severe winds knocking down trees and powerlines.
Montreal
Summer
The summer months of June all the way to mid-September bring warm and hot humid weather. Average daytime temperatures stay between 24 and 28 °C (75 and 82 °F) and overnight temperatures around 16 °C (61 °F). However, temperatures reach and even exceed 30 °C (86 °F) on many days; combined with high humidity, it feels much hotter. Some nights, temperatures remain at an uncomfortable 20 °C (68 °F).
While summer is the sunniest season, short-lived thunderstorms are also common. Rain typically occurs on average between 12 and 13 days per month.
https://en.wikipedia.org/wiki/Geography_of_Montreal#Climate
summers are hot and humid in most of North America east of the Rocky Mountains that's normal. get over it climate alarmists