Summer in Montreal brings a mix of warm days, refreshing breezes, and bursts of rain here and there. Most days, highs land in the mid-20s °C (70s °F), with July usually feeling the hottest. Nights cool off enough to be comfortable, but sometimes the heat and humidity stick around for a few muggy days.
You’ll get plenty of daylight for outdoor plans, with long evenings that just keep going. Sunshine is common, but clouds and passing showers often break up the heat, and quick thunderstorms pop up now and then.
This mix of warmth, moisture, and light keeps summer feeling lively but not too extreme.
If you know what to expect, you’ll plan better—maybe you want to wander Old Montreal, jump into a festival, or just escape into a park. Montreal’s summer climate offers plenty of variety.
When you get a handle on the patterns—temperature, humidity, rainfall, daylight—you can actually make the most of every day.
Overview of Montreal’s Summer Climate
Montreal summers bring steady warmth, long daylight, and a mix of sunny and rainy days. Most of the time, temperatures feel comfortable, with only occasional spells of high humidity or heavier rain.
Location and Climate Classification
Montreal sits on an island in the Saint Lawrence River, tucked into southern Quebec, Canada. Its spot in eastern North America gives it a humid continental climate—warm summers, cold winters, and pretty dramatic seasonal swings in both temperature and daylight.
During summer, average daytime highs reach the mid-70s °F (about 24°C). Nights usually drop to the mid-50s °F (13°C).
On the hottest days, you might see highs close to 85°F (29°C), but Montreal rarely deals with the intense heat you’ll find in some other North American cities.
Humidity tends to climb in July, and some afternoons feel especially muggy. Rainfall averages about 3 inches (75 mm) a month, coming as quick showers or the occasional thunderstorm.
Still, you’ll get plenty of clear or partly sunny days, especially by late August.
This mix of warmth, manageable humidity, and regular rain means city parks and gardens stay lush and vibrant all summer long.
Comparison to Other Seasons
Montreal summers feel mild when you compare them to the city’s long, tough winters. In January, you’re looking at highs near 23°F (-5°C) and lots of snow, while summer brings steady warmth without those extremes.
Spring and autumn show up as quick transition seasons. In April, temperatures hover around 45°F (7°C), while October cools fast with highs near 54°F (12°C).
These seasons tend to be less predictable, with late frosts in spring and early snow in fall.
Daylight shifts a lot too. In June, you get more than 15 hours of light, but by December, it’s less than 9 hours. This huge difference makes summer the best time for outdoor fun, festivals, and waterfront events.
Unlike winter, when winds cut right through you and everything feels icy, summer breezes average about 8 mph (13 km/h) and feel gentle. You’ll find it way more comfortable to explore Montreal’s neighborhoods and culture in summer.
Average Summer Temperatures in Montreal
Summer in Montreal, Quebec, brings steady warmth, long daylight, and evenings that don’t get too chilly. Temperatures rise from the low 70s°F (around 22°C) at the start of summer, peak in mid-July, and then ease a bit in August—still great for being outside.
June Temperature Patterns
June kicks off the warm season in Montreal. Daytime highs average about 22°C (72°F), while nights drop to around 12°C (54°F).
No snow, moderate humidity—June feels like a good time to get out and explore.
You get about 15 to 16 hours of daylight, so there’s lots of time for parks, festivals, and outdoor meals. Rainfall usually lands around 75 mm (2.9 inches), spread over several days, but showers are often short and not too disruptive.
By late June, warmer days can hit 25°C (77°F). It’s really the first month you can count on summer clothes, though a light jacket in the evenings isn’t a bad idea.
July Temperature Trends
July is the hottest month in Montreal. Average highs hit 26°C (79°F), and lows stay near 16°C (61°F), so you get warm days and mild nights.
Humidity can tick up a bit, but it’s usually manageable—not like the tropics.
Daylight sticks around for about 15 hours, and you’ll see sunshine close to 9–10 hours a day. July is perfect for outdoor events and waterfront fun along the St. Lawrence River.
Rainfall is moderate, averaging about 80 mm (3.1 inches). Showers are brief, so most days stay dry and warm.
July evenings feel especially nice, often comfortable long after sunset.
August Temperature Overview
August hangs onto much of July’s warmth but starts to cool off a little. Average highs dip to 25°C (77°F), and lows settle around 15°C (59°F).
The air feels less humid than July, making it easier to stay outside for hours.
Daylight drops to about 14 hours, but sunshine is still strong, averaging near 9 hours per day. There’s no shortage of time for sightseeing, cycling, or outdoor terraces.
Rainfall averages about 78 mm (3 inches), much like July, but showers might feel a bit less frequent. By late August, evenings cool down and you’ll probably want a light sweater, especially near the river or open spaces.
Humidity and Comfort Levels
If you spend time in Montréal during summer, you’ll notice the air can get pretty humid, especially in July and August. The combo of moisture and warm temps really affects how comfortable it feels outside.
Typical Humidity Ranges
Summer humidity in Montréal usually falls between 55% and 70%. You’ll find the lowest averages in late spring, like May, but July and August often reach the higher end.
Mornings tend to feel more humid, with relative humidity peaking before noon. As the day heats up, the percentage drops a bit, but the air can still feel heavy.
Compared to winter, when humidity indoors makes everything feel dry, summer in Québec brings a steady dampness. This can make it feel warmer outside than the thermometer says.
If muggy weather bothers you, try outdoor plans earlier or later in the day when humidity isn’t as noticeable.
Heat Index and Perceived Temperature
The heat index combines air temperature and humidity to show how hot it actually feels. In Montréal, a day at 82°F (28°C) with high humidity can feel closer to 90°F (32°C).
You’ll notice this most in July. Even though average highs sit near 75–80°F (24–27°C), the extra moisture makes it feel hotter and more tiring.
High humidity slows your body’s ability to cool down through sweat. That’s why you might feel sticky or overheated even if the thermometer doesn’t show extreme heat.
To stay comfortable, drink water often, rest in the shade, and use air conditioning or fans inside if you can. These little steps really help with Montréal’s humid summer.
Precipitation and Rainfall Patterns
Montreal gets steady precipitation through summer, with rain spread across many days instead of just a few big storms. You’ll see both light showers and heavier storms, and these really shape the city’s humid summer feel.
Rainfall Amounts and Frequency
In Montreal, summer rainfall averages between 80 mm and 100 mm per month. That’s pretty consistent across June, July, and August.
Rain comes often enough to keep things humid, but rarely does it ruin an entire day.
You can expect 12 to 14 days of measurable rain per month in summer. Some days bring just quick showers, while others might have longer periods of steady rain.
Montreal doesn’t really have a dry summer season. The humid continental climate spreads rainfall throughout the year, so wet days can happen even in July, which is usually the warmest month.
Chance of Wet Days
Montreal’s chance of a wet day in summer is fairly high compared to other Canadian cities. The odds of at least 0.1 mm of precipitation on any given day run from 35% to 45% in June through August.
You’ll see all kinds of rain—from light drizzle to quick thunderstorms. Thunderstorms show up more in July, when hotter air helps them form. These can bring brief heavy downpours, but they usually pass quickly.
Since there’s about a one in three chance of rain, it’s smart to carry an umbrella or light rain jacket if you plan to be outside. This matters even more if you’re hitting parks, festivals, or outdoor markets.
Monthly Precipitation Trends
Monthly rainfall in Montreal during summer follows a steady but slightly varied pattern. June usually gets around 90 mm, with frequent showers as spring transitions to summer. July has the highest chance of thunderstorms, with totals near 95 mm. August stays close to 90 mm, though showers might drop off a bit late in the month.
Here’s a straightforward breakdown:
| Month | Avg. Rainfall (mm) | Rainy Days (avg.) |
|---|---|---|
| June | ~90 mm | 13–14 days |
| July | ~95 mm | 12–13 days |
| August | ~90 mm | 11–12 days |
So, expect fairly even rainfall across the summer—no month really stands out as especially dry.
Cloud Cover and Sunshine
Montreal’s summer skies swing between clear and partly cloudy, giving you a nice balance of sun and shade. As summer goes on, cloudiness drops, and daylight stays long, so you get lots of time outside.
Cloudiness Throughout the Season
Cloud cover in Montreal shifts from June to August. Early summer often starts with more overcast days—cloud cover sits around 50% in June.
By late August, skies clear up, with cloudiness dropping closer to 35–40%.
July usually brings the sunniest stretch. Even if it rains, showers rarely last long, and the rest of the day is bright. That’s why July draws so many outdoor events and festivals.
Cloud patterns also affect how warm the day feels. Clear days can push temperatures into the mid-20s °C (mid-70s °F). Cloudy stretches might keep afternoons a little cooler.
This mix keeps Montreal’s summer comfortable and varied—definitely different from places that swing to extremes.
Sunshine Hours and Daylight Changes
Montreal enjoys long daylight hours in summer, especially in June and July. Around the summer solstice, you can expect about 15½ to 16 hours of daylight—plenty of time to get out and explore.
Sunshine hours peak in July, averaging about 11 hours per day. June and August still have strong sunlight, with around 9–10 hours daily.
As summer moves into September, daylight shortens to about 12½ hours, and sunshine averages drop closer to 8 hours per day. Even then, afternoons stay bright and evenings mild.
The combo of long days and steady sunshine makes Montreal’s summer one of the best times for outdoor fun, from walks in Mount Royal Park to dining on open-air terraces.
Daylight Duration and Sun Position
In Montréal, daylight length shifts a lot through the summer months, and the position of the sun really shapes your time outside.
You’ll notice big differences between June, July, and August in both how long the days last and when the sun comes up and goes down.
Length of Days in Summer
During summer in Montréal, daylight really hits its peak right around the June solstice. You’ll get about 15 hours and 44 minutes of daylight then, which is honestly the longest stretch you’ll see all year.
This extended period of sun feels perfect if you’re hoping to spend more time outdoors, exploring the city or just soaking up nature.
By July, the days are still long, though they start to get a little shorter. You’ll usually have more than 15 hours of daylight, so there’s still plenty of time to do things well into the evening.
July also tends to bring the highest number of sunshine hours, often topping 270 hours in total. That’s a lot of sun, honestly.
In August, daylight drops off a bit faster. By the end of the month, you’re looking at closer to 13½ hours of daylight.
Even as the days get shorter, there’s still enough evening light for a relaxed dinner outside or maybe a walk along the Saint Lawrence River.
Sunrise and Sunset Times
Sunrise and sunset times in Montréal shift gradually over the summer. In late June, the sun usually rises around 5:05 a.m. and sets close to 8:50 p.m.
These early mornings and late evenings definitely stretch the daylight. You really notice how long and bright the days feel.
By mid-July, sunrise comes a bit later, around 5:30 a.m. Sunset slides earlier too, landing at about 8:40 p.m.
If you like early outings, you’ll spot the difference. The change isn’t huge, but it’s there.
August brings a more noticeable shift. Sunrise often happens after 6:00 a.m. and sunset drops closer to 7:45 p.m.
Evenings start to feel shorter. By the end of August, events kick off under dimmer skies.
Here’s a quick look at how things trend:
| Month | Sunrise (approx.) | Sunset (approx.) | Daylight Length |
|---|---|---|---|
| June | 5:05 a.m. | 8:50 p.m. | 15h 44m |
| July | 5:30 a.m. | 8:40 p.m. | ~15h 10m |
| August | 6:00 a.m. | 7:45 p.m. | ~13h 45m |
These shifts influence not just your schedule but also when Montréal feels busiest.