Hottest (avg)
#2 / 12
One of the warmer months.
August in context
How it compares to the rest of the year in Montreal.
Wettest (avg)
#4 / 12
Typical rainfall for the year.
Daylight Hours
#4 / 12
Around the yearly average.
Windiest (avg)
#12 / 12
Usually calmer than most months.
Highest UV
#4 / 12
Near the middle of the yearly UV range.
Most Humid
#7 / 12
Humidity stays close to the yearly norm.
Monthly climate breakdown
A detailed look at the typical climate conditions for August.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
14.1 h
Average daylight
- UV index (max)
- 7
- Typical sun hours
- 04:56 - 18:59
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 14 days
- Cloud cover (avg)
- 54%
Air feel
Humidity & Wind
73%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through August in Montreal. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for August. Temperature 23.8°C.
Historical disruption baseline
Typical disruptions in August
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in August.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 19% of days (5.9 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
5.9 days / month
- Share of days
- ~19% of days
- Upper edge
- Up to ~38mm (P95)
Why this matters
Rain disruption risk appears on ~6 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 17% of days (5.4 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
5.4 days / month
- Share of days
- ~17% of days
- Upper edge
- Up to ~40mm (P95)
Why this matters
Washout conditions are possible on ~5 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 10% of days (3.2 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.2 days / month
- Share of days
- ~10% of days
- Upper edge
- Up to ~47mm (P95)
Why this matters
Heavy rain is possible on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 3% of days (0.8 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~67km/h (P95)
Why this matters
Stormy conditions are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 2% of days (0.5 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~74km/h (P95)
Why this matters
Strong gusts are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Heat Moderate
Hot feels-like days Measures: Hot feels-like days (>=32C). Observed about 2% of days (0.8 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~35°C (P95)
Why this matters
Feels-like heat >=32C is possible on ~1 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Show all disruptions (20 more)
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 1.0 days/month in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.0 days / month
- Share of days
- —
- Upper edge
- Up to ~25mm (P95)
Why this matters
Multi-day washout runs are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 2% of days (0.5 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~103mm (P95)
Why this matters
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Extreme rain Measures: Extreme rain days (>=50mm). Observed about 1% of days (0.2 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~117mm (P95)
Why this matters
Extreme rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Humidity Moderate
Muggy days Measures: Muggy days (dew point >=20C). Observed about 2% of days (0.6 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.6 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~21°C (P95)
Why this matters
Muggy conditions are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 58% of days (17.9 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
17.9 days / month
- Share of days
- ~58% of days
- Upper edge
- Up to ~21mm (P95)
Why this matters
Measurable rain is possible on ~18 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 43% of days (13.4 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
13.4 days / month
- Share of days
- ~43% of days
- Upper edge
- Up to ~99% (P95)
Why this matters
Cloudy skies are possible on ~13 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 41% of days (12.7 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
12.7 days / month
- Share of days
- ~41% of days
- Upper edge
- Up to ~18h (P95)
Why this matters
Several rainy hours are possible on ~13 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 29% of days (9.1 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
9.1 days / month
- Share of days
- ~29% of days
- Upper edge
- Up to ~62km/h (P95)
Why this matters
Gusty conditions are possible on ~9 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 27% of days (8.4 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.4 days / month
- Share of days
- ~27% of days
- Upper edge
- Up to ~19h (P95)
Why this matters
Wet-most-of-day conditions are possible on ~8 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 25% of days (7.8 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
7.8 days / month
- Share of days
- ~25% of days
- Upper edge
- Up to ~92% (P95)
Why this matters
High humidity is possible on ~8 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 21% of days (6.6 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.6 days / month
- Share of days
- ~21% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~7 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
Humid days Measures: Humid days (dew point >=18C). Observed about 12% of days (3.6 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.6 days / month
- Share of days
- ~12% of days
- Upper edge
- Up to ~21°C (P95)
Why this matters
Humid conditions are possible on ~4 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 7% of days (2.3 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.3 days / month
- Share of days
- ~7% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~2 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
Convective risk Measures: Convective storm risk proxy. Observed about 4% of days (1.3 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.3 days / month
- Share of days
- ~4% of days
- Upper edge
- Up to ~21°C (P95)
Why this matters
Convective risk signal appears on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Hot days Measures: Hot days (>=30C). Observed about 2% of days (0.6 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.6 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~32°C (P95)
Why this matters
Hot days are possible on ~1 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Visibility Minor
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 2% of days (0.5 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~95% (P95)
Why this matters
Fog-likely conditions are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 2% of days (0.5 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~95 (P95)
Why this matters
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Warm nights Measures: Warm nights (min >=22C). Observed about 1% of days (0.2 days/month) in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~23°C (P95)
Why this matters
Warm nights are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Heatwave run Measures: Heatwave runs (>=3 hot days). Observed about 0.1 days/month in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.1 days / month
- Share of days
- —
- Upper edge
- Up to ~31°C (P95)
Why this matters
Heatwave runs are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Heat Minor
Feels-like heatwave Measures: Feels-like heatwave runs (>=3 days). Observed about 0.1 days/month in August. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.1 days / month
- Share of days
- —
- Upper edge
- Up to ~32°C (P95)
Why this matters
Feels-like heatwave runs are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is August a good time to visit Montreal?
Typical August days in Montreal reach highs of 23°C (73°F) with nights around 15°C (59°F). It usually feels warm by day and mild after dark. Overall, August sits in the middle of the Montreal climate range.
What are temperatures like in August?
Daytime temperatures in August typically peak near 23°C (73°F), while nights drop to around 15°C (59°F). Expect warm afternoons and mild evenings.
How much does it rain in August?
Rainfall in August averages 101 mm (4.0 in) across roughly 14 days. Overall it is a very wet time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in August?
You can expect about 14 hours of daylight in August. Sunrise is typically around 04:56 and sunset near 18:59. You get long days with comfortable amounts of daylight.
How strong is the sun in August?
UV levels are often high (around 7). Regular sunscreen and a hat are recommended.
Is it windy in August?
In August, average wind speeds are around 10 km/h (6 mph), with gusts on the windiest days reaching about 50 km/h (31 mph). On the ground, it is it often feels breezy, especially in more exposed spots or along the coast.