I went in early November last year and I have to say that queue-wise it was the best trip I've had so far. The longest queue we had was about 15 mins and we managed to get round IOA by lunchtime, even when we went on rides more than once. The weather was ok too, warm enough for shorts, etc but not too hot or cold. Only drawback was the fact it gets dark in the early evening and the parks operate on off-season hours (and we found a fair few rides were having rehabs at this time too.)
Am going in early December this year and hope to have similar queuing times lol!!