Layers
Raincoat (necessary)
- prudent and practical though not always necessary
Comfortable shoes - definitely. Sneakers/runners/gym shoes and good walking shoes/boots.
Jacket for cool nights--combine the raincoat/jacket, she suggests - Mmmm... the nights can be quite mild in June but it is definitely still a good idea. Don't pack winter wear whatever you do!

She didn't say whether heavy sweaters would be necessary for nights. - I wouldn't bother. A light jumper/sweater should be fine.

Now, I know this is probably of little interest to anybody, but I tend to have the worst instincts when it comes to packing for long trips.
Always carry too much, which I can't stand. So I am going to make a big effort here to pack economically. And, if there is a sympathetic
British ear out there who will help, thanks very much in advance.
- Go out light/Come back heavy is my motto. This isn't Iceland here and you should pack sensibly otherwise you'll be lugging around jumpers and heavy clothes all week. Bring light to medium clothes or else wait for a week before you leave and I'll let you know how the Summer is looking. We tend to get few surprises here when it comes to the weather. It is either incredibly beautiful or absolutely torrential but the temperature never goes below 15 degrees C in June. Even now it's 13.6 degrees outside my office window.

1. Will jeans pretty much do it? - Yup.
2. Are heavy sweaters probably necessary at night for those of us who shiver easily? - Nope. Bring lighter ones. A light jacket can make up the difference.
3. Lights-weight tops: Any sense in taking them at all that time of year? (IN other words, should I just leave my sleeveless tops back in the US?) - No. Bring them. But check back with me about the weather in early June.
4. Bathing suits, I would guess, would be pretty much out of the question. - Why? It can be wonderful in the sea at that time of year.

"Maybe I should just carry an empty suitcase and buy everything over there as needed." (I was just kidding, but, if I had a limitless budget--I don't--I'd almost be tempted.)

One thing you should buy is an Aran sweater. I have one for the past two years and wore it most of this winter and, yes, it is very warm. Good for those of you who live in snow and ice zones in North America. I think they cost about $60-70 but you get tax back (21%) at the airport and they should last you a lifetime. You can also get wool socks, caps and gloves. I'm saying nothing about the souvenirs.....