Yes

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

Why? Because it's cold. simple as that.
50°F10°C & Mostly Clear

Wind is 2 mph4 km/h from the N, gusting to 9 mph14 km/h
April 20
6am52°F11°C2 mph3 km/h NEMostly Clear
7am54°F12°C1 mph2 km/h NEPartly Cloudy
8am55°F13°C1 mph2 km/h EPartly Cloudy
9am57°F14°C1 mph2 km/h SEPartly Cloudy
10am57°F14°C2 mph2 km/h SEPartly Cloudy
11am58°F14°C2 mph4 km/h SEPartly Cloudy
12pm57°F14°C3 mph5 km/h SEPartly Cloudy
1pm56°F13°C4 mph6 km/h SEPartly Cloudy
2pm54°F12°C5 mph7 km/h SEMostly Clear
3pm52°F11°C5 mph8 km/h SEMostly Clear
4pm48°F9°C4 mph7 km/h SEClear
5pm46°F8°C3 mph6 km/h EClear
DateLowHighWindDayNight
April 1937°F3°C58°F14°C3 mph4 km/h from NEPartly CloudyMostly Clear
April 2038°F3°C60°F16°C5 mph7 km/h from EPartly CloudyMostly Cloudy
April 2142°F5°C60°F15°C12 mph20 km/h from NWMostly CloudyPartly Cloudy
April 2242°F5°C56°F14°C7 mph12 km/h from NPartly CloudyMostly Clear
April 2337°F3°C54°F12°C7 mph11 km/h from NWMostly CloudyPartly Cloudy
April 2439°F4°C52°F11°C9 mph14 km/h from NMostly CloudyMostly Cloudy
April 2538°F4°C51°F11°C5 mph8 km/h from SWMostly CloudyDrizzle

Yes

Low of 38°F4°C, High of 60°F16°C
Wind: 5 mph7 km/h
Precipitation: None

Support This Page