Montreal sits on an island in the Saint Lawrence River in southern Quebec, at approximately 45.50°N, 73.57°W. It has a humid continental climate (Köppen Dfb) with very cold, snowy winters and warm, humid summers, and four sharply distinct seasons. The nearby Saint Lawrence and Ottawa rivers add moisture to the air, while the city's inland position exposes it to the full swing of the continental temperature range.

Summer, from June to August, is warm and often sultry, with July the warmest and sunniest month — average highs around 26–27°C. High humidity fed by the surrounding rivers can make hot days feel oppressive, occasionally pushing the perceived temperature well above the thermometer reading. Locals half-joke that Montreal has 'two seasons: winter and July'. Afternoon thunderstorms are common, and summer is statistically the wettest season as well as the sunniest.

Winter, from mid-November to mid-March, is long and severe. January, the coldest month, averages highs around -5°C and lows near -13°C — colder on average than Moscow — and cold waves regularly drive temperatures below -25°C, with wind chill making it feel far colder still. Snow is heavy and frequent: the city averages well over two metres a year, and snow normally blankets the ground from late November into March. Freezing rain and ice storms are a recurring winter hazard.

Montreal receives generous precipitation, around 1,000–1,050 mm a year, well distributed across every season with a slight summer maximum from thunderstorms. On top of the rain, more than 200 cm of snow falls in the long winter. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Winter weather here has its own vocabulary: cold snaps arrive with the blizzard, a gusting north wind, or the 'barber', a raw, wet northeasterly off the Gulf of St. Lawrence cold enough to freeze hair and beards. Spring and autumn are shorter transitional seasons prone to sudden swings, and warm early- and late-season 'Indian summer' spells are a regular, cherished feature of the climate.

To follow any single measurement in Montreal more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.