Yes

you do need a jacket based on the weather in Santiago, Santiago Metropolitan Region, Chile 1 second ago

Why? Because it's not very warm out!
54°F12°C & Clear

Wind is 1 mph2 km/h from the East, gusting to 2 mph4 km/h
May 15
1am53°F12°C2 mph3 km/h EastMostly Clear
2am53°F11°C2 mph2 km/h EastMostly Clear
3am52°F11°C2 mph3 km/h EastMostly Clear
4am51°F11°C1 mph2 km/h EastMostly Clear
5am51°F10°C1 mph2 km/h EastMostly Clear
6am50°F10°C1 mph2 km/h EastPartly Cloudy
7am50°F10°C1 mph2 km/h EastPartly Cloudy
8am50°F10°C2 mph3 km/h EastMostly Clear
9am53°F12°C1 mph2 km/h NortheastMostly Clear
10am56°F14°C1 mph2 km/h NorthwestMostly Clear
11am60°F16°C2 mph3 km/h WestClear
12pm63°F17°C2 mph4 km/h SouthwestClear
DateLowHighWindDayNight
May 1550°F10°C68°F20°C3 mph4 km/h from SouthwestClearMostly Clear
May 1650°F10°C67°F19°C3 mph4 km/h from SouthwestMostly ClearMostly Cloudy
May 1750°F10°C60°F15°C3 mph4 km/h from SouthDrizzleDrizzle
May 1850°F10°C62°F17°C1 mph2 km/h from SouthCloudyDrizzle
May 1953°F12°C68°F20°C2 mph4 km/h from SouthDrizzleMostly Cloudy
May 2055°F13°C71°F22°C1 mph2 km/h from EastMostly CloudyMostly Cloudy
May 2156°F13°C73°F23°C2 mph3 km/h from SouthwestPartly CloudyPartly Cloudy

Yes

Low of 50°F10°C, High of 67°F20°C
Wind: 3 mph4 km/h
Precipitation: None

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