December to February
Go nowThe least hot months, and mostly dry
Warm days, nights mild enough for a light layer, and little rain. Now and then a north wind brings a grey, fresher day or two. January is the city's anniversary month: it was founded on the sixth, a fixed date, and weeks of free concerts follow. Christmas and New Year fill the hotels with Mexican families.
November
Go nowThe rains ending, and the days of the dead
The storms thin out, the countryside is green and the heat eases to its winter level. The turn of October into November is the Maya version of the Day of the Dead, on fixed dates, with altars in the squares and, a few days earlier, a night-time procession from the main cemetery; rooms fill for those days. The rest of the month is quiet and good.
March
Worth it, butDry, and heating up week by week
Still dry, with the temperature climbing. On and around the spring equinox, about the twentieth, crowds gather at Chichén Itzá to watch the shadow move down the pyramid's stair. Holy Week moves between March and April, and Mérida empties towards the coast, which is then full.
June to August
Worth it, butHot and humid, with afternoon storms
Rain on more than half the days, usually a heavy downpour late in the afternoon that cools the air for an hour. Mornings are for the sites, and the cenotes are at their best when the day is at its worst. Mexican school holidays in July and August keep the beaches and the big ruins busy.
September and October
Worth it, butStorm season, and the cheapest weeks
Frequent storms, high humidity and the peak of the hurricane season in the Gulf and the Caribbean. Mérida is inland and direct hits are rare, but a storm anywhere in the region can cancel flights and flood roads. Prices are at their lowest and the sites are empty.
April and May
Think twiceThe hottest weeks of the year
The end of the dry season, before the rain breaks: afternoons that stop everything, hot nights, and a haze from fields being burned for planting. Sightseeing shrinks to the first hours of the morning. If these are your only dates, book a pool, start at dawn and write off the hours from noon to five.