Yes

you do need a jacket based on the weather in Lisbon, Portugal 1 second ago

Why? Because the wind is harsh and biting!
77°F25°C & Partly Cloudy

Wind is 10 mph16 km/h from the Southwest, gusting to 19 mph31 km/h
September 6
12pm77°F25°C10 mph17 km/h SouthwestPartly Cloudy
1pm75°F24°C10 mph16 km/h WestPartly Cloudy
2pm73°F23°C9 mph15 km/h WestMostly Cloudy
3pm70°F21°C8 mph12 km/h WestMostly Cloudy
4pm68°F20°C7 mph11 km/h WestMostly Cloudy
5pm67°F20°C6 mph9 km/h SouthwestMostly Cloudy
6pm67°F19°C6 mph9 km/h SouthwestCloudy
7pm67°F19°C6 mph9 km/h SouthwestCloudy
8pm67°F19°C6 mph9 km/h SouthwestCloudy
9pm67°F19°C5 mph8 km/h SouthwestCloudy
10pm66°F19°C5 mph8 km/h SouthRain
11pm66°F19°C5 mph8 km/h SouthRain
DateLowHighWindDayNight
September 559°F15°C78°F26°C7 mph11 km/h from SouthwestPartly CloudyRain
September 665°F18°C78°F26°C6 mph9 km/h from NorthwestDrizzleMostly Cloudy
September 761°F16°C73°F23°C13 mph21 km/h from NorthPartly CloudyMostly Clear
September 859°F15°C72°F22°C14 mph23 km/h from NorthwestPartly CloudyPartly Cloudy
September 962°F17°C77°F25°C9 mph15 km/h from NorthwestPartly CloudyPartly Cloudy
September 1065°F18°C81°F27°C9 mph14 km/h from NorthMostly ClearMostly Clear
September 1163°F17°C80°F26°C11 mph18 km/h from NorthMostly ClearMostly Clear

No

Low of 64°F18°C, High of 78°F26°C
Wind: 6 mph9 km/h
Precipitation: 67% rain

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