Yes

you do need a jacket based on the weather in San Francisco, CA 94102, USA 4 minutes ago

Why? Because it's pretty chilly!
55°F13°C & Partly Cloudy

Wind is 7 mph12 km/h from the Southwest, gusting to 14 mph23 km/h
June 12
11am55°F13°C8 mph12 km/h WestMostly Cloudy
12pm58°F14°C7 mph11 km/h SouthwestPartly Cloudy
1pm61°F16°C7 mph12 km/h SouthwestMostly Clear
2pm63°F17°C9 mph14 km/h WestMostly Clear
3pm65°F18°C10 mph16 km/h WestMostly Clear
4pm67°F19°C12 mph19 km/h WestMostly Clear
5pm68°F20°C13 mph22 km/h WestClear
6pm68°F20°C15 mph24 km/h WestClear
7pm65°F19°C13 mph22 km/h WestMostly Clear
8pm65°F18°C13 mph22 km/h WestMostly Clear
9pm63°F17°C13 mph21 km/h WestMostly Clear
10pm62°F17°C12 mph20 km/h WestMostly Clear
DateLowHighWindDayNight
June 1252°F11°C68°F20°C11 mph18 km/h from WestMostly ClearMostly Clear
June 1353°F12°C65°F18°C10 mph17 km/h from WestMostly ClearPartly Cloudy
June 1452°F11°C65°F18°C8 mph14 km/h from SouthwestPartly CloudyPartly Cloudy
June 1552°F11°C63°F17°C10 mph16 km/h from SouthwestMostly CloudyPartly Cloudy
June 1652°F11°C67°F19°C10 mph15 km/h from SouthwestMostly ClearClear
June 1754°F12°C72°F22°C7 mph12 km/h from WestClearMostly Clear
June 1856°F13°C75°F24°C8 mph13 km/h from WestClearClear

Yes

Low of 53°F12°C, High of 64°F18°C
Wind: 10 mph17 km/h
Precipitation: None

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