I have my favorites around here, you know wunderground.com, intellicast.com and the old standby weather.gov (not the commercial one).
But what about overseas? Sure you can select one of the others, but usually better info can be had from the government sponsored site, like this one for Iceland (http://en.vedur.is/). Even if in a foreign language, Chrome can translate the pages.
Always check to see if one is local at your travel destination!