Yes

you do need a jacket based on the weather in Trieste, Province of Trieste, Italy 1 second ago

Why? Because it's not very warm out!
59°F15°C & Cloudy

Wind is 2 mph3 km/h from the South, gusting to 10 mph16 km/h
October 20
11am59°F15°C2 mph4 km/h SouthCloudy
12pm60°F16°C2 mph3 km/h SouthwestCloudy
1pm60°F16°C2 mph3 km/h SouthwestCloudy
2pm60°F16°C2 mph3 km/h WestCloudy
3pm59°F15°C2 mph4 km/h SouthCloudy
4pm59°F15°C4 mph6 km/h SouthDrizzle
5pm58°F14°C4 mph6 km/h SouthDrizzle
6pm58°F14°C4 mph6 km/h SouthDrizzle
7pm57°F14°C3 mph6 km/h SouthDrizzle
8pm57°F14°C4 mph6 km/h SouthDrizzle
9pm57°F14°C4 mph7 km/h SouthDrizzle
10pm57°F14°C4 mph7 km/h SouthDrizzle
DateLowHighWindDayNight
October 1950°F10°C60°F16°C3 mph5 km/h from SoutheastDrizzleRain
October 2057°F14°C61°F16°C8 mph13 km/h from SouthRainRain
October 2156°F13°C63°F17°C3 mph6 km/h from SouthwestDrizzleDrizzle
October 2258°F15°C64°F18°C9 mph14 km/h from SouthRainRain
October 2352°F11°C63°F17°C7 mph11 km/h from SouthPartly CloudyPartly Cloudy
October 2450°F10°C61°F16°C4 mph7 km/h from SouthRainRain
October 2548°F9°C58°F14°C7 mph11 km/h from EastDrizzleDrizzle

Yes

Low of 57°F14°C, High of 61°F16°C
Wind: 8 mph13 km/h
Precipitation: 92% rain

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