Yes

you do need a jacket based on the weather in Hamilton, ON, Canada 1 second ago

Why? Because it's cool. Pleasantly cool, but cool.
50°F10°C & Cloudy

Wind is 11 mph18 km/h from the SW, gusting to 21 mph34 km/h
April 24
12am50°F10°C11 mph18 km/h SWDrizzle
1am49°F10°C12 mph19 km/h SWMostly Cloudy
2am49°F9°C11 mph18 km/h SWMostly Cloudy
3am48°F9°C11 mph18 km/h SWMostly Cloudy
4am47°F9°C10 mph15 km/h WMostly Cloudy
5am47°F9°C8 mph13 km/h WCloudy
6am47°F9°C6 mph9 km/h WCloudy
7am47°F8°C7 mph11 km/h NWCloudy
8am46°F8°C11 mph17 km/h NCloudy
9am43°F6°C14 mph22 km/h NCloudy
10am41°F5°C14 mph22 km/h NCloudy
11am40°F5°C13 mph22 km/h NCloudy
DateLowHighWindDayNight
April 2347°F8°C64°F18°C14 mph23 km/h from SWMostly CloudyDrizzle
April 2436°F2°C50°F10°C12 mph19 km/h from NPartly CloudyClear
April 2533°F1°C49°F10°C7 mph12 km/h from EClearClear
April 2635°F1°C54°F12°C10 mph16 km/h from NEMostly ClearRain
April 2746°F8°C64°F18°C12 mph19 km/h from SRainDrizzle
April 2858°F15°C71°F22°C13 mph21 km/h from SWMostly CloudyMostly Cloudy
April 2955°F13°C75°F24°C12 mph20 km/h from SWMostly CloudyRain

Yes

Low of 37°F3°C, High of 50°F10°C
Wind: 12 mph19 km/h
Precipitation: 31% rain

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