Yes

you do need a jacket based on the weather in 21000, Split, Croatia 1 second ago

Why? Because it's cool. Pleasantly cool, but cool.
52°F11°C & Cloudy

Wind is 8 mph13 km/h from the NE, gusting to 14 mph23 km/h
April 18
7pm51°F11°C9 mph14 km/h NECloudy
8pm51°F10°C9 mph14 km/h NECloudy
9pm50°F10°C9 mph14 km/h NECloudy
10pm50°F10°C9 mph15 km/h NECloudy
11pm50°F10°C10 mph16 km/h NECloudy
April 19
12am50°F10°C11 mph18 km/h NECloudy
1am51°F10°C13 mph20 km/h NECloudy
2am52°F11°C13 mph22 km/h NECloudy
3am54°F12°C14 mph23 km/h NEMostly Cloudy
4am56°F13°C14 mph23 km/h NEMostly Clear
5am58°F15°C14 mph22 km/h NEMostly Clear
6am60°F16°C12 mph20 km/h NEClear
DateLowHighWindDayNight
April 1850°F10°C64°F18°C11 mph18 km/h from NEMostly ClearPartly Cloudy
April 1946°F8°C60°F16°C5 mph8 km/h from SWMostly CloudyRain
April 2048°F9°C58°F14°C10 mph16 km/h from NECloudyPartly Cloudy
April 2145°F7°C61°F16°C6 mph10 km/h from SEMostly ClearMostly Cloudy
April 2248°F9°C63°F17°C7 mph11 km/h from NWMostly CloudyDrizzle
April 2348°F9°C59°F15°C6 mph9 km/h from SDrizzleMostly Cloudy
April 2448°F9°C60°F16°C5 mph9 km/h from SEPartly CloudyClear

Yes

Low of 46°F8°C, High of 61°F16°C
Wind: 5 mph8 km/h
Precipitation: None

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