Yes

you do need a jacket based on the weather in King of Prussia, PA, USA 1 second ago

Why? Because it's not very warm out and the wind could blow a wig clean off your head!
59°F15°C & Cloudy

Wind is 10 mph16 km/h from the West, gusting to 24 mph38 km/h
October 20
11pm57°F14°C8 mph12 km/h WestClear
October 21
12am55°F13°C8 mph13 km/h WestClear
1am53°F12°C8 mph12 km/h WestClear
2am52°F11°C7 mph12 km/h WestClear
3am52°F11°C8 mph12 km/h WestClear
4am51°F10°C7 mph11 km/h WestClear
5am50°F10°C6 mph10 km/h WestClear
6am49°F9°C6 mph9 km/h WestClear
7am48°F9°C5 mph9 km/h WestClear
8am47°F8°C5 mph8 km/h WestClear
9am46°F8°C4 mph7 km/h WestClear
10am45°F7°C4 mph7 km/h SouthwestClear
DateLowHighWindDayNight
October 2051°F10°C67°F20°C9 mph14 km/h from WestPartly CloudyClear
October 2145°F7°C69°F20°C7 mph12 km/h from SouthMostly ClearDrizzle
October 2248°F9°C61°F16°C11 mph17 km/h from WestMostly ClearMostly Clear
October 2344°F7°C57°F14°C10 mph16 km/h from WestPartly CloudyClear
October 2441°F5°C57°F14°C8 mph13 km/h from WestMostly ClearMostly Clear
October 2538°F3°C57°F14°C4 mph6 km/h from NorthwestMostly CloudyMostly Cloudy
October 2640°F4°C60°F16°C4 mph6 km/h from SouthPartly CloudyMostly Clear

Yes

Low of 45°F7°C, High of 69°F21°C
Wind: 7 mph12 km/h
Precipitation: None

Support This Page