Yes

you do need a jacket based on the weather in Helensburgh, UK 2 minutes ago

Why? Because just cool enough for a jacket, but not warm enough to ditch it!
53°F12°C & Mostly Clear

Wind is 9 mph15 km/h from the East, gusting to 15 mph24 km/h
April 24
7am54°F12°C10 mph15 km/h EastMostly Clear
8am56°F13°C10 mph16 km/h EastMostly Clear
9am57°F14°C10 mph16 km/h EastPartly Cloudy
10am58°F14°C10 mph16 km/h EastPartly Cloudy
11am58°F15°C10 mph16 km/h EastMostly Clear
12pm58°F14°C9 mph15 km/h EastPartly Cloudy
1pm57°F14°C10 mph15 km/h EastPartly Cloudy
2pm56°F13°C9 mph15 km/h EastPartly Cloudy
3pm54°F12°C8 mph13 km/h EastMostly Clear
4pm51°F11°C8 mph13 km/h EastPartly Cloudy
5pm49°F10°C8 mph12 km/h EastPartly Cloudy
6pm48°F9°C8 mph12 km/h EastMostly Cloudy
DateLowHighWindDayNight
April 2342°F5°C58°F15°C9 mph14 km/h from EastPartly CloudyMostly Cloudy
April 2443°F6°C57°F14°C10 mph16 km/h from SoutheastCloudyRain
April 2548°F9°C57°F14°C7 mph11 km/h from SouthDrizzleMostly Cloudy
April 2647°F9°C58°F15°C11 mph18 km/h from SouthwestDrizzleCloudy
April 2751°F11°C60°F15°C9 mph14 km/h from SouthwestCloudyCloudy
April 2847°F8°C66°F19°C5 mph8 km/h from SouthMostly CloudyPartly Cloudy
April 2949°F9°C67°F20°C5 mph8 km/h from SoutheastPartly CloudyMostly Clear

Yes

Low of 43°F6°C, High of 56°F14°C
Wind: 10 mph16 km/h
Precipitation: None

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