Yes

you do need a jacket based on the weather in Szczecin, Poland 1 second ago

Why? Because it's cold. simple as that.
45°F7°C & Mostly Clear

Wind is 10 mph16 km/h from the SW, gusting to 20 mph32 km/h
March 28
7pm45°F7°C10 mph16 km/h SWMostly Clear
8pm44°F7°C10 mph16 km/h SWMostly Clear
9pm43°F6°C10 mph17 km/h SWPartly Cloudy
10pm43°F6°C10 mph15 km/h SWPartly Cloudy
11pm42°F6°C8 mph13 km/h SWMostly Clear
March 29
12am42°F6°C9 mph14 km/h SMostly Clear
1am41°F5°C9 mph14 km/h SPartly Cloudy
2am43°F6°C9 mph15 km/h SMostly Cloudy
3am45°F7°C10 mph15 km/h SMostly Cloudy
4am48°F9°C11 mph18 km/h SCloudy
5am50°F10°C12 mph19 km/h SCloudy
6am52°F11°C12 mph20 km/h SCloudy
DateLowHighWindDayNight
March 2745°F7°C57°F14°C12 mph19 km/h from SWCloudyPartly Cloudy
March 2841°F5°C57°F14°C12 mph19 km/h from SCloudyMostly Cloudy
March 2943°F6°C69°F21°C9 mph14 km/h from SEPartly CloudyMostly Clear
March 3049°F9°C65°F18°C8 mph13 km/h from SWMostly CloudyPartly Cloudy
March 3145°F7°C66°F19°C9 mph14 km/h from SEMostly CloudyRain
April 143°F6°C52°F11°C13 mph21 km/h from WDrizzleDrizzle
April 240°F4°C52°F11°C8 mph13 km/h from SCloudyMostly Cloudy

Yes

Low of 42°F6°C, High of 57°F14°C
Wind: 12 mph19 km/h
Precipitation: None

Support This Page