The best time to visit Belize

What a year in Belize looks like

Belize runs a dry season from about February to May and a wet one from roughly June to November, the latter sitting exactly on top of the Atlantic hurricane season. What you actually feel is not temperature, which stays warm all year, but underwater visibility and how settled the sea is, because those decide whether the boat to the Great Blue Hole or the snorkel at Hol Chan happens at all. Inland, the rainforest and the cave systems answer to water differently: heavy rain can make the underground rivers too strong to enter on a given day. There is a wildlife calendar too, with whale sharks off Gladden Spit typically appearing around the full moons of roughly March to June.

The year, in windows

• December to January — High season opens and the air is at its most comfortable of the year, with lower humidity and nights cool enough to sleep well. The thing to know is the northers: pulses of wind coming down from the north that kick up the sea and cut underwater visibility for a couple of days at a time, with some boats standing down on the windiest of them. Christmas to New Year is when the island lodges are fullest and dearest, so that fortnight needs booking early.
• February to April — The heart of the dry season, with the calmest sea and the clearest water of the year, which is when a Great Blue Hole day trip has its best chance of actually sailing. Inland the dirt roads to the Maya sites and caves behave, and the underground rivers sit at a safe level. April warms up noticeably, and on certain days cruise arrivals make Belize City and the nearest sites markedly busier, so ask which days those fall on before planning a mainland excursion.
• May to July — A shoulder season: the rain returns as afternoon storms but the sea usually still lets boats out, rates have come off the winter peak and everything is still open. These are the months when whale sharks gather at Gladden Spit around the full moon, which for a lot of divers is the only reason to choose them. The forest greens up and the rivers rise. Humidity climbs noticeably from about the middle of June onward, and that alone changes how much walking a day can hold.
• August to November — Full wet season and the busiest part of the Atlantic storm season, particularly September into early October, when some island resorts close for refurbishment. Prices are at their lowest, and the trade is boats that cannot sail on some days and underwater visibility that drops after heavy rain washes sediment out. On the mainland it is the opposite story: the forest is at its most alive, the waterfalls are full, and you will have the Maya sites nearly to yourself. By late November things settle again.

The weeks to aim for

If the reef is the point, aim at February to April: the calmest sea, the clearest water, and the lowest chance of the year that a boat day gets cancelled. For a trip that wants both the cayes and the mainland, March gives dry access roads to the Maya sites and cave rivers at a safe level at the same time. Anyone coming specifically for whale sharks has to plan around the full moons in roughly March to June, and should allow several spare days, because nothing about an encounter can be promised.

The weeks to avoid

September and early October are the hardest weeks to defend, because they are the peak of the hurricane season and a fair number of lodges close for maintenance. The prices are genuinely low, but the trade is days when the boats stay in and water that turns cloudy after heavy rain. Christmas to New Year is the opposite trade: the weather is at its best and the rooms on Caye Caulker and Ambergris are at their fullest and dearest. January carries the northers, which can quietly erase two or three diving days. All of it is doable — the point is knowing which trade you are making.

What the season does to a data plan

Belize is a country where plans move because of the sea, and the news that tomorrow's boat is off usually reaches you as a message the night before rather than as a notice on a website — which makes a working data line worth more here than its size suggests. On Caye Caulker and Ambergris the signal is solid in the village and thins as the boat heads out toward the reef. On the mainland, the roads into the forest and to the Maya sites have stretches of several kilometres with nothing at all, so download the map before you leave town. In the wet season the afternoon storms send everyone indoors early, and the hours spent online checking the next day's outlook and rebuilding the schedule add up. When a storm takes the power out, the lodge Wi-Fi goes with it.