<P> In the northeastern parts of Ontario , extending far as south as Kirkland Lake , the cold waters of Hudson Bay depress summer temperatures , making it cooler than other locations at similar latitudes . The same is true on the northern shore of Lake Superior , which cools hot humid air from the south , leading to cooler summer temperatures . Along the eastern shores of Lake Superior and Lake Huron winter temperatures are slightly moderated but come with frequent heavy lake - effect snow squalls that increase seasonal snowfall totals upwards of 3 m ( 10 ft ) in some places . These regions have higher annual precipitation in some case over 100 cm ( 39 in ) . The northernmost parts of Ontario -- primarily north of 50 ° N -- have a subarctic climate ( Köppen Dfc ) with long , severely cold winters and short , cool to warm summers with dramatic temperature changes possible in all seasons . With no major mountain ranges blocking sinking Arctic air masses , temperatures of − 40 ° C ( − 40 ° F ) are not uncommon ; snowfall remains on the ground for sometimes over half the year . Snowfall accumulation can be high in some areas . Precipitation is generally less than 70 cm ( 28 in ) and peaks in the summer months in the form of showers or thunderstorms . </P>
<P> In the northeastern parts of Ontario , extending far as south as Kirkland Lake , the cold waters of Hudson Bay depress summer temperatures , making it cooler than other locations at similar latitudes . The same is true on the northern shore of Lake Superior , which cools hot humid air from the south , leading to cooler summer temperatures . Along the eastern shores of Lake Superior and Lake Huron winter temperatures are slightly moderated but come with frequent heavy lake - effect snow squalls that increase seasonal snowfall totals upwards of 3 m ( 10 ft ) in some places . These regions have higher annual precipitation in some case over 100 cm ( 39 in ) . The northernmost parts of Ontario -- primarily north of 50 ° N -- have a subarctic climate ( Köppen Dfc ) with long , severely cold winters and short , cool to warm summers with dramatic temperature changes possible in all seasons . With no major mountain ranges blocking sinking Arctic air masses , temperatures of − 40 ° C ( − 40 ° F ) are not uncommon ; snowfall remains on the ground for sometimes over half the year . Snowfall accumulation can be high in some areas . Precipitation is generally less than 70 cm ( 28 in ) and peaks in the summer months in the form of showers or thunderstorms . </P>
how cold does it get in ontario canada
how cold does it get in ontario canada
temperatures of − 40 ° C ( − 40 ° F ) are not uncommon
temperatures of − 40 ° C ( − 40 ° F ) are not uncommon