Where to dive, month by month

The shape of the year

Ask where to dive in a given month and the usual answer is a list of ten places that barely changes from January to December. Our records say something different. Every area we cover carries a rating for each of the twelve months — off-season, fair, good or prime — and when you read those ratings across the whole map at once, the year is not flat at all. It has a high summer, a long low winter, and two shoulders that behave differently in different seas.

The summer plateau is the striking part. From June to September, close to half the places we rate are at their best, and the reason is that four large regions open at the same time: the Mediterranean, the North Atlantic islands, the cold-water coasts of northern Europe and North America, and the Pacific coast of the Americas. None of them is diveable in comfort in January, and all of them are in July. Then the plateau ends abruptly. October takes a third of it away as the Mediterranean shuts, November takes another slice, and by the low point of the year fewer than one place in five is at its best — more than twice as many places are prime in July as in November.

The trough is not empty. It is concentrated. What is at its best in November sits almost entirely in the coral triangle, the Indian Ocean, East Africa and the Red Sea shoulder, and that is what the November section below is about. The rest of the year, the story is which seas are opening and which are closing, and this guide goes through it a month at a time. Under the matrix at the end is the part that matters most: what a month rating means, and what it does not.

January

January is the Caribbean’s month, and the month the far south opens. Most of the Caribbean is rated prime from December or January through April — the trade winds are steady, the hurricane season is over, and the water is at its clearest. The same dry northeast monsoon settles the Maldives, so Ari & Rasdhoo Atolls and its neighbours are prime from January to April with the calmest seas and clearest water of their year. And the Antarctic ships are sailing: the Antarctic Peninsula is reachable only in the austral summer, and January sits in the middle of it.

Two cold-water places make January distinctive rather than just warm. Skjervøy is a January dive because the herring are: the orcas follow the fish into the fjords for the winter and disperse when the herring do in late winter, so the window is short and the timing is the fish’s, not the diver’s. And Djibouti — Gulf of Tadjoura is at its whale-shark peak, with the plankton bloom in the Gulf of Tadjoura pulling juveniles in along the shore from November to February. Further east, Raja Ampat is in the calm half of its year, October to April, when the crossings are smoothest and the water clearest.

February

The one month with a dive that exists in no other. Shiretoko Drift Ice is rated prime in February only, because the drift ice from the Sea of Okhotsk reaches the Hokkaido coast in a narrow window, and outside it there is nothing to dive under. It is the shortest season on the map.

February is also when the two great whale seasons of the northern winter are running at once. Silver Bank off the Dominican Republic has its humpbacks from roughly December to mid-April, but the permitted trips run only from late January into early April, so February and March are the whole practical season. And in the Andaman Sea, the Similan Islands are at the peak of their manta and whale-shark months, December to March, inside a park that will close in May. Palau is in its dry season, November to April, and Misool is at one of its two visibility peaks, February to March.

March

The Caribbean is at its fullest — nearly every area we rate there is prime this month — and this is the last full month before the coral-triangle spring takes over the calendar. Cozumel is the pick of it: January to April is its prime, the leeward side calm under lighter trades, with the only interruption a winter norte that can shut the port for a day. Across in the Bahamas, Bimini is closing its great-hammerhead season, which is most consistent from December to March.

March also opens two windows that are about one animal. Farasan Banks & Al Lith off Al Lith is where juvenile whale sharks gather at Shib Habil from March to May, in a region that will be unworkable by midsummer. And in the eastern Pacific, Revillagigedo (Socorro) is in the last stretch of a liveaboard season that runs from mid-November to May, with the humpbacks passing through from January to March. In Thailand, Richelieu Rock has its best whale-shark odds from February to April, when the plankton peaks.

April

April belongs to the Philippines and Borneo. It is the month Tubbataha Reefs opens: the park permits diving only from mid-March to mid-June, closed the rest of the year for the monsoon and for the reef’s recovery, so the whole season is three months long and April is the heart of it. Malapascua is prime in April and May, the northeast monsoon over and the dawn crossing to the thresher shoal no longer at risk of cancellation. And Layang-Layang is reachable at all only when its single resort is open, roughly March to August, with the hammerhead schooling at its peak from March to May.

The Red Sea’s first shoulder starts here. Most of the Egyptian coast is rated prime in April and May and again in September and October, because spring and autumn bring the calmest seas for the offshore crossings; Hurghada & El Gouna is exactly on that pattern, and the Brothers & Daedalus liveaboards run a version of it, prime from May into June and again in September and October, with a pause over the rough winter months.

May

May is the shoulder month in both directions, and the last quiet one before the summer opens. The Caribbean is thinning fast — most of its areas drop from prime to good or fair as the hurricane season approaches — while the coral triangle reaches its annual high. In the Red Sea, Sharm El Sheikh — Ras Mohammed starts a prime run that lasts until October. In the Philippines, Dauin is at the calm end of its year on a sheltered coast, the trade-wind chop of December to February long gone from its sand slopes; in Borneo, Sipadan is inside a long prime run from March to September.

Two May places are unusual. Zeeland in the Netherlands is a cold, green estuary and is prime for exactly one reason: the cuttlefish come in to breed from April to June, and it is the year’s highlight. And Cenderawasih Bay enters its dry season, May to October, which does not change the whale sharks — they are at the bagans all year — but does calm the long liveaboard crossings to reach them.

June

June is the month the map changes most. The Mediterranean goes from almost nowhere rated prime in May to almost everywhere, because the season there is short and sharp: warm water, settled seas and the dive centres fully open from June to September. Malta & Gozo is the example, with its warmest water and calmest seas in those four months. The cold-water coasts open at the same time — Scapa Flow charters run most reliably in the calmer, longer-daylight summer, and the same is true of most of Britain, Scandinavia and the Canadian coasts.

The eastern Pacific turns over too, and the other way from what warm-water logic would suggest. Galápagos — Darwin & Wolf is rated prime from June to November, the cool, nutrient-rich garúa season of drizzle and fog, because that is when the biggest hammerhead schools and the whale sharks arrive; the calmer, clearer months of December to May have fewer sharks. Komodo starts its June to October prime on the strongest upwelling and the best visibility of its year. And on the Wild Coast of South Africa, the Wild Coast Sardine Run peaks in June and July, inside a migration that starts in May; some years the shoal is thin or absent, which is why it is rated the way it is.

July

The richest month of the year, and by a wide margin. Everything June opened is still open, and the North Atlantic adds itself: the Azores — Pico & Faial have their warm water, calmer swell and peak mobula activity at the seamounts from June to September, and the Princess Alice Bank crossing, on that site’s own record, runs from the beginning of July to mid-October. In the Pacific, Fakarava is prime in June and July for the grouper spawning aggregation in the south pass and the shark density that comes with it. British Columbia — Browning Pass runs June to September, when the operators do; the water is famously clearer in winter, and almost nobody goes.

The Mediterranean is at full stretch, with the Medes Islands at their warmest and busiest with grouper, and the coral triangle’s dry-season places, Kimbe Bay among them, are at their clearest. July is the month when the honest answer to “where should I dive” is “almost anywhere you can reach”, and that is exactly why it is worth knowing which places are only open now.

August

August is the humpback month in the South Pacific. Vava'u is prime from July to October, when the whales are in the islands and the seas are calm, and Niue pairs the same whales with a July to September peak. In the far north, Svalbard is diveable only in the polar summer, June to September, and the expedition ships are sailing.

Two August places are about one event. On the Flower Garden Banks, the corals spawn a few nights after the August full moon, inside a charter season that runs roughly April to October when the Gulf is calm. And at Baa Atoll & Hanifaru Bay in the Maldives, the Hanifaru aggregation of mantas runs from May to November on the southwest monsoon and peaks from August to October, which makes it the rare Maldivian place whose prime months are the wet ones, the opposite of the rest of the country’s calendar.

September

The high summer’s last month, and quietly the best for two coasts. The Mediterranean is still rated prime nearly everywhere — Crete is warmest June to October, with the meltemi’s worst behind it after August — and the American Atlantic and Pacific coasts hit their peak. The North Carolina Wrecks have their sand-tiger aggregations at their densest in September and October, and Monterey Bay gets its calmest surf and clearest water of the year in the autumn, once the summer upwelling settles.

September also reopens the Red Sea’s second shoulder. Elsewhere it turns on a set of places that run on warm water rather than calm: Cabo Pulmo has its bull sharks and mobula aggregations from June to November, and the Seychelles — Inner Islands inner islands have whale sharks passing through the channels from August to October, ahead of their calmest inter-monsoon weeks.

October

October is the month the year folds. The Mediterranean closes almost completely; the cold-water coasts have already gone; the Caribbean is at the bottom of its year with the hurricane peak just past. The places that are prime in October are the ones built for it. The Red Sea is on its second shoulder, Marsa Alam & Port Ghalib with the calmest seas for Elphinstone in spring and autumn. The Banda Islands open their liveaboard transit season, October to April, and Rowley Shoals off north-west Australia run only in a short window from September to December, before the Kimberley wet and the cyclones close them.

In the south, Puerto Madryn & Península Valdés starts its best sea-lion months, September to March, with the right whales still in the gulf. And in the Atlantic, La Palma rates September to November best, when the trades ease and the water is warmest.

November

The quietest month of the diving year. Fewer than one place in five that we rate is at its best in November, because four regions are between seasons at once: the Caribbean is in the tail of the hurricane season, the Mediterranean is shut, the cold-water summer is months gone, and South-East Asia is waiting for the northeast monsoon to settle the Andaman Sea. What is left is concentrated and, for the most part, very good.

Raja Ampat returns to prime in November, at the start of its calm October to April half, and Triton Bay further down the same coast opens its core season, November to February, on a shore too rough for the rest of the year. Cocos Island is in the last month of its rainy-season prime — the nutrient-rich water that brings the densest hammerhead schools runs June to November. Magdalena Bay on the Pacific side of Baja is a November dive and almost nothing else: the striped-marlin baitball season on the banks outside the bay runs October to December and peaks in November, and the operators do not run outside it. And Socotra, which the southwest monsoon closes entirely from June to September, is in one of its two calm windows, October and November.

December

December is the year turning back. The Caribbean returns, half its areas prime again by this month and most by January — Bonaire sits south of the hurricane belt and is rated prime from December to April on the calmest end of an already calm year. The Philippine dry season starts, and Coron has its clearest water on the wrecks from November to May. In the south, the austral summer opens Rapa Nui (Easter Island), calmest and warmest from December to March, and Kaikōura is warmest and calmest from November to March, with the sperm whales and seals present all year.

And one December dive is about cold water arriving, not leaving. At Crystal River in Florida, the manatees crowd into the springs from November to March, when the Gulf of Mexico drops below 20 °C and the constant spring water is the warmest place they can find.

The whole year in one figure

Read down any column and the shape of the chart above reappears: the June to September block is solid on the European and North American rows, the December to April block on the Caribbean, Maldivian and Andaman rows, and the two eastern Pacific rows at the bottom light up in the months almost everything else goes dark.

What a month rating means

The colours in that matrix are ratings for diving conditions in that month, at that site’s area: sea state, whether the boats run, whether the park is open, how clear the water tends to be. They are not an animal calendar, and the two can point in opposite directions at the same place.

Komodo is the clearest case. Its prime months are June to October, the dry season with the strongest upwelling and the best visibility. Its mantas are a wet-season sight at the southern sites, December to March, when the area is rated only good. A diver who books Komodo in July for the visibility gets the visibility; one who books it in July for mantas at Manta Alley has read the colours as a promise they were never making.

Cocos Island and Galápagos — Darwin & Wolf run the other way. Both are rated prime in the rainy, cooler, rougher half of the year, June to November, because that is when the hammerheads school densest and the whale sharks arrive. The dry season is calmer and clearer, and a diver who wants the easiest conditions would choose it; a diver who wants the sharks would not. In those two areas the rating follows the animals because the operators’ seasons were built around the animals. In most of the world it follows the weather.

Silfra is the honest extreme. Its water is filtered glacial groundwater at the same temperature and clarity in every month, and its own record says so: the ratings track daylight hours and road access to Þingvellir, not anything underwater. It is rated prime from May to September because that is when it is easiest to get to and see.

So: use the ratings to know when the sea is likely to let you dive. Use the area and site pages, and the animal guides in this section, to know when the thing you are travelling for is likely to be there. Where the two disagree, the site’s own record wins, and this guide has been written to say nothing those records contradict.

Planning around it

The other fixed dates are the storm seasons. The Atlantic hurricane season runs from 1 June to 30 November, with its statistical peak on 10 September, which is why the Caribbean thins from May and why Cozumel’s and Grand Cayman’s records name September and October as the highest-risk months. The South Pacific and Australian cyclone seasons run the opposite half of the year, from November to April, and that is the reason Tonga, Niue, Fiji and the Coral Sea are all dry-season, winter-to-spring destinations in our ratings and the Kimberley shoals close for the wet.

The last thing to plan around is the shoulder. Both Red Sea shoulders, April to May and September to October, are rated prime for the calmest crossings, and they are also when the liveaboards to the offshore reefs are running at full stretch. The Maldives’ two inter-monsoon periods are the calmest weeks there. And October, the month the year folds, is worth a second look on its own: the Mediterranean’s few October holdouts — Crete, Cyprus, Kaş, Cabo de Palos and Sète among them — are the last warm-water diving in Europe before the six-month close, and the Red Sea, Baja, the Banda Sea and north-west Australia are all opening at once.