Yes

you do need a jacket based on the weather in London Borough of Barnet, UK 1 second ago

Why? Because it's not very warm out and the wind is offering free, unsolicited face massages!
54°F12°C & Partly Cloudy

Wind is 9 mph14 km/h from the Southwest, gusting to 19 mph31 km/h
September 11
2am54°F12°C9 mph15 km/h SouthwestPartly Cloudy
3am55°F13°C10 mph17 km/h SouthwestPartly Cloudy
4am57°F14°C12 mph19 km/h SouthwestPartly Cloudy
5am59°F15°C13 mph21 km/h SouthwestPartly Cloudy
6am61°F16°C13 mph21 km/h SouthwestPartly Cloudy
7am63°F17°C14 mph22 km/h SouthwestPartly Cloudy
8am64°F18°C15 mph24 km/h SouthwestPartly Cloudy
9am63°F17°C15 mph24 km/h SouthwestMostly Cloudy
10am61°F16°C14 mph23 km/h SouthwestRain
11am62°F17°C14 mph22 km/h SouthwestPartly Cloudy
12pm61°F16°C14 mph22 km/h SouthwestPartly Cloudy
1pm60°F15°C14 mph22 km/h SouthwestPartly Cloudy
DateLowHighWindDayNight
September 1053°F12°C64°F18°C13 mph21 km/h from SouthwestRainPartly Cloudy
September 1151°F11°C64°F18°C12 mph19 km/h from SouthwestDrizzleDrizzle
September 1252°F11°C64°F18°C11 mph17 km/h from SouthwestDrizzlePartly Cloudy
September 1350°F10°C65°F19°C12 mph19 km/h from SouthRainRain
September 1455°F13°C63°F17°C20 mph32 km/h from SouthwestDrizzlePartly Cloudy
September 1553°F12°C63°F17°C13 mph21 km/h from WestMostly CloudyMostly Cloudy
September 1650°F10°C65°F19°C12 mph20 km/h from SouthwestDrizzleMostly Cloudy

Yes

Low of 52°F11°C, High of 64°F18°C
Wind: 12 mph19 km/h
Precipitation: 45% rain

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