The Yucatán holds Chichén Itzá's Pyramid of Kukulcán, Tulum's cliff-edge Mayan ruins above the Caribbean, and 6,000+ cenote sinkholes feeding the world's longest underwater cave system at Sac Actun.
Trade-wind dry season with Riviera Maya beaches at peak, Day of the Dead at Mérida late October, and Equinox at Chichén Itzá March 21 casts the serpent shadow.
Whale shark season off Isla Mujeres mid-May to mid-September, sea calmest for diving Cenote Dos Ojos, and the Yucatán green before the heaviest rains.
Hurricane season peaks September with elevated Caribbean risk, but the cenotes stay reliably accessible and Mérida's interior position gives some shelter from coastal storms.
Hurricane risk fading, Day of the Dead in late October-early November fills Mérida cemeteries, and the high-season buildup begins for Tulum and Playa del Carmen.