Cozumel Reefs in August

November through April delivers the best conditions. Water visibility peaks at 120+ feet, and the north winds stay calm. December and January see the most divers, so book accommodations early. But here's what dive operators won't tell you: May through October offers warmer water (84°F vs 78°F) and fewer crowds, just with occasional rain showers. Hurricane season runs June through November, though direct hits are rare. The worst months? September and October bring the highest storm risk. Christmas week costs double everything else, and Easter week runs a close second. Book shoulder seasons — November or April — for the sweet spot of good weather and reasonable prices.