I know you can't predict the weather....but what temps should I expect between 4/21 - 5/8/08. Traveling in Budapest, Prague, and southern England. I have traveled in years past earlier in April in Italy, Ireland, Paris, etc. and found it usually cool--sometimes cold. Trying to pack very light as going solo.
At that time of year substantially colder than California. Budapest should be the warmest.
Check out weather underground at http://www.wunderground.com/ Look under the trip planner section - that way you can look at the historical records to give you a good idea at what to expect.