Montreal in September
In September, Montreal averages 21°C (70°F) during the day and 13°C (55°F) at night, with frequent rain — about 14 days of the month see precipitation (80 mm total).
High seasonConditions are comfortable for sightseeing without being sweltering. Plan for unsettled weather and bring rain gear.
September offers comfortable temperatures in Montreal, with some rain to plan around.
How September compares to the rest of the year in Montreal
September is in the middle of the year for warmth in Montreal (4th of 12) and one of the driest months (12th of 12). Daytime temperature runs 10°C above the annual average (12°C). September runs 4°C cooler than August (25°C) and cools 7°C in October (14°C).
September sunrise & sunset in Montreal
Times shown for Montreal local time (America/Montreal), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Montreal — September
Golden-hour and blue-hour windows for the 15th of September, in Montreal's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Montreal in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (High season) and Montreal's popularity.
Crowds & pricing — September in Montreal
This is a busy month in Montreal — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: excellent tourism weather
Sun & mosquito risk — September in Montreal
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Montreal in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | -5°C / 23°F | -13°C / 8°F | 74 mm | 17 | — |
| February | -3°C / 26°F | -13°C / 9°F | 80 mm | 17 | — |
| March | 2°C / 36°F | -7°C / 20°F | 81 mm | 18 | — |
| April | 11°C / 51°F | 1°C / 33°F | 120 mm | 17 | — |
| May | 19°C / 67°F | 9°C / 47°F | 70 mm | 16 | — |
| June | 24°C / 74°F | 14°C / 58°F | 121 mm | 19 | — |
| July | 26°C / 79°F | 18°C / 64°F | 95 mm | 20 | — |
| August | 25°C / 77°F | 17°C / 63°F | 109 mm | 20 | — |
| September | 21°C / 70°F | 13°C / 55°F | 80 mm | 14 | — |
| October | 14°C / 57°F | 7°C / 44°F | 135 mm | 18 | — |
| November | 6°C / 42°F | -1°C / 30°F | 80 mm | 17 | — |
| December | 0°C / 31°F | -7°C / 19°F | 91 mm | 16 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Montreal in September →
Frequently asked questions
How hot is Montreal in September?
In September, Montreal averages a high of 21°C (70°F) and a low of 13°C (55°F) — generally mild and pleasant.
Does it rain a lot in Montreal in September?
September can be fairly wet in Montreal, with about 14 rainy days on average.
Is September a good time to visit Montreal?
September is mild and pleasant but on the rainy side. It suits travelers who are comfortable with mild and pleasant weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Montreal in September?
Pack light layers for warm days and cooler evenings, plus a compact umbrella or rain jacket. See the full September packing list for Montreal for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.