Weather Accuracy

I've worked outside in a T-shirt on Christmas Day once, and half-frozen to death on a mountain in summer, despite multiple state-of-the-art layers. You never know what you're in for!

I've never experienced severe cold except at high altitudes, and the wind chill itself isn't that bad - it's the rain+wind chill that's the problem. If you're wind- and rain-proofed you should be fine. I wouldn't bother with an umbrella outside towns though, they blow away.

If hiking, I take along an extra pair of trousers in my day-backpack, because, even when the weather's fine, chances are it hasn't been in the previous 24 hours, and any long grass/ vegetation will be wet, and your clothes will soak through quickly. While you wear one pair, the other can dry a little, draped over your backpack (yup, such a sexy look;) with the help of all those otherwise-irritating straps and buckles backpack manufacturers insist on. Bear in mind that denim doesn't dry very fast!

Have fun!

You can always wear waterproof trousers over your jeans.... hey presto, walk into the pub for lunch, take your wet trousers off and you'rve a dry pair underneath!

Have been to Ireland several times in the summer and always needed a rain jacket, long pants, and a long sleeved fleece for some evenings. Have also had to buy a wool sweater for warmth during the summer. It varies, but you can always buy something warm.