Yes

you do need a jacket based on the weather in Malahide, Co. Dublin, Ireland 1 second ago

Why? Because it's on the windy side!

70°F21°C & Mostly Cloudy

Wind is 10 mph16 km/h from the Southwest, gusting to 20 mph32 km/h

Date	Low	High	Wind	Day	Night
June 15	54°F12°C	70°F21°C	8 mph12 km/h from Southwest	Partly Cloudy	Mostly Cloudy
June 16	58°F14°C	68°F20°C	9 mph15 km/h from Southwest	Mostly Cloudy	Partly Cloudy
June 17	52°F11°C	65°F18°C	5 mph9 km/h from Southwest	Partly Cloudy	Mostly Clear
June 18	56°F14°C	67°F20°C	9 mph15 km/h from Southeast	Mostly Clear	Partly Cloudy
June 19	59°F15°C	69°F21°C	11 mph17 km/h from Southeast	Mostly Cloudy	Mostly Clear
June 20	61°F16°C	70°F21°C	9 mph14 km/h from Southeast	Partly Cloudy	Partly Cloudy
June 21	61°F16°C	72°F22°C	6 mph10 km/h from South	Mostly Cloudy	Partly Cloudy

Low of 58°F15°C, High of 68°F20°C
Wind: 9 mph15 km/h
Precipitation: 16% rain