Weather in the United Kingdom

i would. i traveled in september (temps in the 50s-60s) and found that a tank longsleeve button up shirt and my trench coat were plenty. it depends on how sensitve to hot/cold you are. i did a lot of walking so that helped keep me warm. but layers are good. when i went i had 3 button ups and 4 tanks that i switched around so layers does not need to mean a packing a tons of clothes.

Layering is always the best choice for UK weather. A light weight water resistant jacket or umbrella (brolley) are always good choices.

Dressing in layers is the best plan. A fleece layer under a technical waterproof jacket with a hood is way to dress while walking the walls of all those Castles. The UK is not as formal as it used to be, but a step up from jeans is good. A couple of nice sweaters. A couple of wash and wear shirts. A wool sport jacket for nice days and for going out to dinner and the theater. And waterproof or resistant comfortable shoes. Maybe a tie-down hat. April might still have snow in the north. May is just wet. I think September has the best weather.

More chance of settled weather in May and the daylight hours are longer. Still waiting for the trees to break bud this year! If you do travel in April (next year?) try and avoid the couple of weeks around Easter ie 18 - 22 April. Kids on school holiday so museums etc very busy.

Kyle, check the extended forecast just before you pack. While it does not rain nearly as much in the UK as legend says, weather the last few years seems to have been even less predictable than ever, thanks to climate change. (If the jetstream is tracking south of the UK, you will, though, probably see rain, if this year is any example.) I find the dressing-in-layers thing to be pretty annoying. I mean, you're always going to be taking off and putting on a sweater or something else as you come and go, especially as you come indoors and go outside. For April/May, I'd pack a couple of sweaters and a light rain-proof, wind-proof jacket, ideally one with removable lining. Then I'd check the forecast before I headed out for each day. No one would be terribly surprised of it snowed in April or hit 80F (pretty warm in the UK) in May.

j.c. makes a very good point. When I was a child everyone knew the rhyme "March winds and April showers bring forth May flowers", and most years it seemed to be accurate, but in the last 10 years that has become less true. London actually gets less rainfall than Paris, or Sydney, believe it or not (probably not, if you had been here this winter and 'spring'). Our 5 day weather forecasts are as accurate as 2 day forecasts were 30 years ago. I use the one on the BBC website, and this: http://www.metoffice.gov.uk