Yes

you do need a jacket based on the weather in Seattle (First Hill), Washington, United States 1 second ago

Why? Because it's cool. Pleasantly cool, but cool!
53°F11°C & Cloudy

Wind is 4 mph7 km/h from the North, gusting to 7 mph12 km/h
October 30
9pm53°F12°C5 mph8 km/h NorthCloudy
10pm54°F12°C5 mph8 km/h NorthCloudy
11pm55°F13°C4 mph7 km/h NorthCloudy
October 31
12am53°F12°C4 mph6 km/h NorthMostly Cloudy
1am51°F11°C4 mph6 km/h NortheastMostly Cloudy
2am49°F10°C2 mph3 km/h NorthMostly Cloudy
3am47°F9°C4 mph6 km/h NorthwestMostly Clear
4am46°F8°C2 mph4 km/h NorthMostly Clear
5am46°F8°C2 mph3 km/h SoutheastPartly Cloudy
6am46°F8°C3 mph5 km/h SoutheastMostly Cloudy
7am45°F7°C4 mph7 km/h SoutheastMostly Cloudy
8am44°F7°C4 mph7 km/h SouthPartly Cloudy
DateLowHighWindDayNight
October 3043°F6°C55°F13°C3 mph5 km/h from NorthMostly CloudyMostly Cloudy
October 3143°F6°C53°F11°C5 mph8 km/h from SouthRainRain
November 147°F8°C56°F14°C9 mph14 km/h from SouthRainDrizzle
November 244°F7°C54°F12°C4 mph6 km/h from SouthPartly CloudyCloudy
November 344°F6°C51°F11°C5 mph9 km/h from NortheastRainRain
November 446°F8°C54°F12°C5 mph7 km/h from SouthRainRain
November 550°F10°C57°F14°C8 mph13 km/h from SouthRainDrizzle

Yes

Low of 44°F7°C, High of 53°F12°C
Wind: 5 mph8 km/h
Precipitation: 82% rain

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