Yucatan Peninsula
Yucatan Peninsula Geography & Climate
Geography
The Yucatan Peninsula is a slab of porous limestone lifted out of the sea, and almost everything about it follows from that single fact.
No rivers
The peninsula is flat — barely anything reaches sixty metres — and the limestone is so permeable that rainfall sinks straight through it. There are almost no surface rivers. Instead the water collects in a vast underground aquifer and moves seaward through flooded cave systems, and where the roof of a cave collapses, a cenote opens.
Cenotes and caves
There are thought to be more than six thousand cenotes, and they connect: the Sac Actun and Ox Bel Ha systems near Tulum run for hundreds of kilometres and are among the longest underwater caves known anywhere. The water is fresh, cold and extraordinarily clear, with a halocline where it meets seawater underground.
The Chicxulub crater
Buried beneath the north-west of the peninsula is the impact crater of the asteroid that struck 66 million years ago and ended the age of the dinosaurs. It is about 180 kilometres across, invisible at the surface, and its rim is marked by a distinct arc of cenotes — the fractured rock along the edge collapses more readily.
Water as the whole story
Because there is no surface water, every settlement on the peninsula — Maya and modern alike — had to be sited on a cenote or a well. The distribution of ancient cities maps almost exactly onto the distribution of accessible groundwater, and the sacred status of cenotes follows from the same fact. The Sacred Cenote at Chichen Itza, dredged in the early twentieth century, yielded gold, jade and human remains thrown in as offerings.
The reef
The Mesoamerican Barrier Reef runs down the Caribbean side, the second largest in the world after Australia’s.
Forests and wetland
Dry scrub in the north grading into tall tropical forest at Calakmul, with mangrove and lagoon along both coasts.
Climate Patterns
The Yucatan has a tropical climate that is hot in every month, and what changes through the year is the rain and the humidity.
The dry season
November to April brings 27 to 31°C, lower humidity and very little rain. December and January are the most comfortable, occasionally cooled by a norte, a cold front pushing down from North America that can drop temperatures for a few days and roughen the sea.
The wet season
May to October is hotter — 33 to 36°C in May, which is the peak — and much more humid, with heavy afternoon downpours that usually pass quickly. Mosquitoes are worse, the vegetation is green, and prices fall.
Hurricanes
The season runs June to November, peaking from August to October, and the peninsula is directly in the Atlantic track. Wilma stalled over Cancun for two days in 2005 and Gilbert devastated the coast in 1988. Building standards have improved and warning is good, but a storm means closed airports, evacuation of the barrier islands and days of disruption. Insurance covering it matters in those months.
Sargassum
Since about 2015, large quantities of drifting seaweed have reached the Caribbean beaches in some years, mostly between April and August. It varies enormously and the Gulf side is unaffected.
Why May is the hard month
Visitors assume the hottest months are July and August, and on the Yucatan they are not. May is the peak — the dry season has been baking the limestone for six months, the rains have not yet arrived to break the heat, and inland towns regularly pass 38°C with no relief. It is also the cheapest month before the rains, which is the trade-off.
Cenote water
A constant 24 to 25°C year round, which feels cold against the air and is the best relief available in May.