Hi, Just a suggestion, we went on 1st September to Cuba. I've been to Mexico (worked on cruise ships for years so been to most places) and Cuba is much cheaper and just as nice. It was really hot every day.
We went to Guadalavaca (south west side) it's really lovely, beautiful beaches, great hotels etc., all inclusive is probably best. We went on a safari, which we had to get a helicopter to, there's an aquarium where you can swim with the dolphins, the nightlife was good, there was diving and the people are so friendly, not after your money all the time like they can be in some places. I'd highly recommend it.
Good luck, hope you find somewhere and enjoy it!