Well, depends on what you mean by weather sites. If you mean weather info in general and particular then perhaps various university and
government agencies are the place to go. I like UCAR a lot.
If you mean weather data and
forecast then again I would recommend govt agencies. I found NOAA info excellent for the W Atlantic, Norwegian Met Office excellent for the
Nordic, etc.. And, again, universities - e.g. Victoria gives good
forecast for the S Pacific and the Islands, etc..
b.