We had a 2 and 1/2 hour guided walk tour (History of Terror) today in Belfast. This was quite an interessting tour, but it was grey, cloudy, wet, cold and windy. It is in prime summertime right now, but it felt like a bad November day.
Believe it or not, yesterday when we were on a hiking tour in Dublin/Howth, my DW got a sunburn in the heck. It was not hot, but when the clouds give way to the sun it might burn quickly.
So yes, bring all possible clothing with you😊