Yes

you do need a jacket based on the weather in Napa, CA 94559, USA 1 second ago

Why? Because it's not very warm out!
52°F11°C & Clear

Wind is 1 mph2 km/h from the North, gusting to 2 mph4 km/h
October 29
12pm52°F11°C2 mph3 km/h NorthClear
1pm51°F11°C2 mph4 km/h NorthClear
2pm51°F10°C3 mph5 km/h NorthwestClear
3pm51°F11°C4 mph6 km/h NorthwestClear
4pm56°F13°C3 mph5 km/h NorthwestClear
5pm63°F17°C2 mph3 km/h WestClear
6pm68°F20°C3 mph4 km/h SouthwestClear
7pm72°F22°C3 mph5 km/h SouthwestClear
8pm76°F24°C3 mph5 km/h SouthwestClear
9pm78°F26°C3 mph6 km/h SouthClear
10pm80°F26°C4 mph6 km/h SouthwestClear
11pm80°F27°C4 mph6 km/h SouthwestClear
DateLowHighWindDayNight
October 2951°F10°C80°F27°C3 mph5 km/h from SouthwestClearMostly Clear
October 3051°F11°C71°F22°C5 mph8 km/h from SouthwestPartly CloudyPartly Cloudy
October 3149°F10°C75°F24°C4 mph6 km/h from WestMostly ClearClear
November 149°F10°C74°F23°C3 mph5 km/h from SouthwestClearMostly Clear
November 249°F10°C76°F24°C3 mph4 km/h from SouthwestClearPartly Cloudy
November 353°F11°C71°F22°C5 mph8 km/h from SouthwestPartly CloudyPartly Cloudy
November 452°F11°C69°F21°C4 mph7 km/h from SouthwestPartly CloudyThunderstorms

Yes

Low of 52°F11°C, High of 72°F22°C
Wind: 5 mph8 km/h
Precipitation: None

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