W e a t h e r
The climate of Ireland is mild, moist and changeable with abundant rainfall and a lack of temperature extremes.
Ireland's climate is defined as a temperate oceanic climate, a classification it shares with most of northwest Europe.
Several layers of clothing to cope with different conditions are better than one thick heavy layer. Conditions at altitude are almost always much cooler and windier than at a lower level. The layering principle of outdoor clothing allows you to cope with widely differing conditions by adding or removing layers as required. Pay particular attention to the base layer because this must wick moisture away from the body without causing too much heat loss. Thermal fabrics are much better than cotton in this respect. Fleece makes a good choice for an intermediate layer.
Your footwear should be of high quality, well fitting, comfortable, preferably waterproof, and give good ankle support. They are probably the most important part of your kit. Take advice from a good specialist retailer. If you own a pair of GAITERS you'll be glad you brought them, TRAINERS are NOT suitable for the mountains!!!
Ask to have your feet measured and take your favourite hunting socks with you to the shop or ask the retailer to recommend suitable socks before trying the boots on.
This does not have to be particularly large, but it should be comfortable and well fitting. It will need space enough to contain a spare pair of socks, upper body clothing layers, a water bottle, space for a packed lunch, and whatever else you may deem necessary such as a camera.