Yes

you do need a jacket based on the weather in Thessaloniki, Greece 1 second ago

Why? Because it's not very warm out.
58°F15°C & Clear

Wind is 6 mph9 km/h from the N, gusting to 17 mph27 km/h
April 25
5pm58°F14°C6 mph9 km/h NClear
6pm57°F14°C6 mph9 km/h NClear
7pm56°F13°C5 mph9 km/h NClear
8pm55°F13°C5 mph8 km/h NClear
9pm54°F12°C5 mph7 km/h NClear
10pm53°F11°C4 mph7 km/h NClear
11pm52°F11°C4 mph7 km/h NClear
April 26
12am53°F11°C4 mph7 km/h NClear
1am54°F12°C5 mph8 km/h NClear
2am57°F14°C5 mph9 km/h NWClear
3am60°F16°C7 mph11 km/h NWClear
4am63°F17°C7 mph12 km/h NWClear
DateLowHighWindDayNight
April 2458°F14°C67°F19°C3 mph5 km/h from NWMostly CloudyClear
April 2552°F11°C72°F22°C5 mph8 km/h from NWClearMostly Cloudy
April 2654°F12°C73°F23°C3 mph4 km/h from SEMostly CloudyClear
April 2756°F13°C76°F25°C5 mph8 km/h from SWClearClear
April 2857°F14°C77°F25°C4 mph7 km/h from SWClearMostly Clear
April 2960°F15°C76°F25°C5 mph7 km/h from WMostly ClearMostly Clear
April 3058°F15°C76°F25°C5 mph8 km/h from SWPartly CloudyMostly Clear

Yes

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

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