Weather in Montréal in May

Shoulder season. May sits in between. You will get good days and you will lose some. You should expect rain on 15 days of the month, which is more days wet than dry.

May ranks 5 of 12 in Montréal: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 15 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 17 °C days and 6.4 °C nights; the spread matters more here than any single number.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest May day reached 29.8 °C and the coldest night fell to -4 °C, and the wettest single day dropped 38 mm — roughly 41% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 168 mm against 32 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 93 mm average is a reasonable planning figure, not a promise.

Wind is light at 10.9 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 79%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way up: 7.8 °C warmer than April, and June adds another 4.8 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in May

14.9 hours of daylight, gaining 1.2 hours across the month. That is between Montréal's extremes of 15.7 and 8.7 hours, so days are long enough not to constrain the plan.

An inland climate

Montréal has no sea to moderate it, and it shows: 43.1 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Montréal versus nearby

If Montréal is one option among several, the nearby comparison is worth making. Sherbrooke is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Ottawa is a better bet in May — within a degree on temperature, 1 day less rain.

So: May works, with September the better month by 16 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Montréal

See all twelve months in Montréal, or where else to go in May.