Funny, summer seems to suck for flying
My log book shows that winter has been excellent for flying, whilst summer has been non stop cancelled lessons. Funny the number of people coming into the flight school enquiring about learning to fly thinking summer is better. I'd actually start around October \ November time and get your night rating into the bargain.
I do what other's here suggest. I tend to book 4 lessons, 2 either side of lunch on a Saturday, and the same on the Sunday. If I get all 4 then I make up for lost time elsewhere, if I don't then you may get _some_ flying.
I also make sure though, that if the lesson is cancelled that you sit down with your instructor for an hour or so and get through the books. I've generally passed an exam when I couldn't fly.
Don't underestimate how quickly you'll get to the test. I know it seems a long way off now but it will come quicker than you think. You don't want to get there and have to wait a month or so because you don't have your 7 exam passes (exactly where I am now). So if you can't fly, crunch through the books and get another exam done.