Keep in mind that there is a lot of french people who doesn't speek English. But people here in Toulouse seem to welcome you. I think for two months it's very doable, it worths it.
And sure the weather is fine, especially in winter :).
As Cyril said there is the international students, but also all the people living here to work with Airbus and the aeronautics and technology field. They usually speek an at least professional english. There is the Café Des Langues in the bar Le Cactus, like every two weeks, where people come to speak different languages. You can find the dates on the CouchSurfing Events, maybe elsewhere.
So i think that for a few months, that definitly worths the try !