My favourite type of weather has to be hot and sunny. And dry. It's got to be dry weather. I hate, really, really hate rain. I like mild winters but not Atlantic driven ones. In fact, although I'm a mild lover I would prefer cold dry days in winter to mild, grey wet ones. Overall though, hot sunshine is my favourite.
As for why I prefer this type of weather ... well there is so much more one can do outdoors when it's sunny and dry. Plus getting up in the morning is so much easier when it's warm and the sun is shining. Cold, wet days just make me feel like turning over and going back to sleep