Yes

you do need a jacket based on the weather in Montreal, QC, Canada 4 minutes ago

Why? Because the drizzle is not enough rain to call it "raining," but enough to make you a little soggy and the air feels like the cozy middle ground between summer and winter and it's on the windy side!
54°F12°C & Drizzle

Wind is 10 mph16 km/h from the Southeast, gusting to 19 mph31 km/h
May 22
4pm53°F12°C10 mph16 km/h SoutheastDrizzle
5pm52°F11°C12 mph19 km/h SoutheastRain
6pm51°F11°C10 mph16 km/h SoutheastDrizzle
7pm51°F10°C9 mph15 km/h EastCloudy
8pm50°F10°C8 mph13 km/h EastCloudy
9pm50°F10°C7 mph11 km/h EastCloudy
10pm49°F9°C7 mph11 km/h EastCloudy
11pm49°F9°C8 mph13 km/h EastCloudy
May 23
12am48°F9°C8 mph13 km/h EastCloudy
1am47°F9°C8 mph12 km/h EastCloudy
2am47°F8°C7 mph12 km/h EastCloudy
3am47°F8°C7 mph12 km/h NortheastCloudy
DateLowHighWindDayNight
May 2248°F9°C54°F12°C8 mph13 km/h from EastRainDrizzle
May 2345°F7°C51°F11°C9 mph15 km/h from NortheastDrizzleDrizzle
May 2444°F6°C53°F12°C6 mph9 km/h from NorthwestDrizzleMostly Cloudy
May 2546°F8°C62°F16°C6 mph9 km/h from NorthwestMostly CloudyPartly Cloudy
May 2648°F9°C71°F22°C5 mph8 km/h from WestMostly ClearMostly Clear
May 2752°F11°C75°F24°C5 mph8 km/h from WestMostly ClearMostly Cloudy
May 2856°F13°C75°F24°C5 mph7 km/h from SoutheastMostly CloudyPartly Cloudy

Yes

Low of 45°F7°C, High of 51°F11°C
Wind: 9 mph15 km/h
Precipitation: 74% rain

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