5:53 p.m. on April 19, 2009 (EDT)
Buying gear is a real challenge, so good on you for doing all this research. I don't know for certain what the weather in Ireland is like in summer, but I have a good idea from a website-somewhere between around the mid 30's to high 60's-low 70's F.
Don't buy stuff randomly. You want everything to work together in layers that can be put on and taken off as the weather changes. Outerwear needs to be big enough to fit over fleece jackets, for example. Raingear-same thing, big enough to fit over everything else. Think of your (or her) clothes as a system where all the parts have to fit together.
If she has time, I am sure there are stores in Dublin that carry local and European brands.Things like wool sweaters-heavy, but durable, should be readily available.
Something like this works great in that kind of weather, not sure what you can find like it here or in Ireland-
http://www.swanndri.co.nz/default.aspx?T=2&P=4
These are really made for guys, but you can't beat them for working or hiking in crappy weather. When I lived in NZ, several of my friends had them. Way pricey these days, unfortunately, but there might be something like them over there.
Based on that, here is what I recommend from skin out-
Base Layer:
synthetic underwear-cotton will get damp; take several pairs of panties which can be washed out easily;
long underwear - a base layer like Capilene, Smart Wool or similar base layer consisting of a top and bottom. I have Capilene-lasts a long time (mine is over 20 years old), washes easily and I even wear my top by itself under a fleece jacket. Mine is a turtleneck with a short zip-sold by Patagonia. Not cheap, but a top brand.
Socks - wool or synthetic. I have Smart Wool and Capilene socks. She can buy wool socks in Ireland if she needs extras.
Gloves - a synthetic lightweight glove like the OR PS150 or similar; REI sells similar gloves made by different companies;
Outer gloves - a waterproof outer glove like a lightweight ski glove; if she is doing field work, a pair of treated leather gloves from your local hardware store that will fit over the liner gloves.
Hat - a brimmed hat like a Tilley-they make a lot of different models;
a fleece beanie of some type; I have one made by Turtlefur.
Insulated layer-
A fleece or wool jacket-full zip, high collar with pockets; I have a Columbia that have used for years, not too expensive, mine is probably a 200 wt.
Insulated jacket-doesn't have to be Gore-tex, but something with a synthetic fill. Stay away from down-not cold enough for it REI will have several.
Pants-a pair of fleece pants would be nice. If you can find a pair with a full zip on the legs, even better-this way she can take them off without taking off her boots. These are mostly for sitting around at night if she is tent camping.
Wind pants-lightweight nylon works, like cheap running pants-these won't be waterproof.
Jeans- a pair to wear in town; stay away from wearing them in the field, lightweight wool or a synthetic would be better for that.
Shorts-not a bad idea, even in mild weather
T-shirts-if the weather is going to be mild, a T-shirt or two is fine.
Rain gear- I have Precip pants and an REI Elements jacket. Get a jacket with pit zips which helps in warm weather.
A word about Gore-tex and similar fabrics-
These fabrics only work under certain conditions, in particular, cold (but not super cold) weather. EVent breathes better than Gore-tex. In warm weather, there isn't enough of a temperature differential for these fabrics to breathe as advertised so you feel clammy anyway because you sweat in them and the moisture will not pass through the fabric. Anyone who tells you different doesn't understand how they work.
Boots-get something that fits. Gore-tex is fine if it's going to be wet, which is likely, but don't expect them to keep feet perfectly dry. Overboots like the Neos should be good for boggy ground. Never used them but they have a good reputation. They can be sized to fit over boots or trail runners. I recommend something with good ankle support if working on steeps; too easy to twist an ankle otherwise.
The usual other stuff-sunglasses, etc.