In two seasons, there's only been one occasion when it rained at match time. Even then, the rain stopped just before kick-off. (Yes, we have that super power.) It does rain in Toronto in summer but it's not the drizzly English kind of rain. Given that we watch Toronto FC in the snow, I think we know to bring a rain mac if it's going to rain and a coat if it's going to be cold.
Wolfpack have been very clear that we're staying at Lamport. No doubt there will be some improvements, but the stadium is owned by the city of Toronto and so any changes have to be negotiated.