Where to Go Diving -- and When

If you're traveling overseas for a diving vacation, don't just research one liveaboard versus another, or which Indonesian resort has WiFi. You also need to research prevailing regional conditions -- such as weather, temperatures, and dry and wet seasons -- before deciding where to go and when to go there. Undercurrent has a lot information in its Seasonal Dive Planners (see "Plan Your Dive Trip" on the left side of our homepage at www.undercurrent.org, and click on any destination listed below it). I recently asked our travelin' contributors Bret Gilliam, John Bantin and Maurine Shimlock to give us their notes on seasonal conditions at top dive destinations, and the best times to visit.

The Carribean and Southern Atlantic

The Caribbean. John Bantin prefers to go between January and June, because "I find the weather is more stable and the rain less persistent." Bret Gilliam says his optimal conditions are from late April into September, "because the brisk trade winds abate then, and sea conditions are milder. Also, rates will generally be lower for hotels and resorts, as well as airfares." Of course, you have to consider that hurricane season officially runs from June into late October. Honduras can get wind and rain from December to February. In the Caymans, it lasts through the winter and later, meaning the Cayman Aggressor frequently cannot make the crossing to the smaller islands.

The Bahamas. The same conditions generally prevail as in the Northeastern Caribbean -- with one exception. "If you want a getaway in winter periods, understand that the Bahamas are in the North Atlantic and can sometimes get quite chilly, both underwater and above," says Gilliam. "I've been in the Abacos in January when night temperatures on land have hit the low 40s -- that's definitely 'sweater weather' for a lot of people." I'll add that one winter only a 7mm Farmer John could keep me warm, though the following summer I dived just in swim trunks. Bantin agrees with the chilly weather, "but I've experienced some of the best diving in the first half of the year." If you choose an area protected by island lee shores or large-scale reefs, you have a much better chance of getting good diving conditions -- Gilliam recommends the Exumas or the Crooked Island archipelago for good diving with excellent protection. "If you're taking a liveaboard, keep in mind that transits can be dicey in winter, depending on your port of embarkation and your route."

Florida Keys. They have pretty much the same conditions as the Bahamas, but rough weather has more effect on visibility. Gilliam says most sites are relatively shallow, but corals have declined dramatically. Good operators make an effort to get to good sites, but there are a lot of 'cattle boats' that don't strain themselves. And it can be cold in winter."

The Pacific

Hawaii. Most folks find that these waters require a 3-mm suit most of the year, but winter temps can drop and a 5-mm (for some divers) is needed to remain comfortable during long dives. October to April -- especially December and January -- bring storms, and lots and lots of rain can fall.

Guadalupe Island. This Mexican site is reached from the mainland port of Ensenada and has perhaps the best great white shark diving in the world. Gilliam recommends a late-June to October period for visits, "but even in summer, water temps will rarely get above 70 degrees, so pack at least your 3-mm or 5-mm wetsuit." Some readers have reported temperatures below 60 degrees.

Sea of Cortez. Water temperatures can get into the mid-80s from late September to mid-November, then gradually decrease into the low 70s and 60s until May or so, then they begin to climb once again. But temperatures vary at depth, and vary north to south; in Cabo San Lucas, where the Sea and the cold Pacific meet, water temperatures can swing wildly.

Cocos Island. To experience its awesome diving, the best conditions are June through September for marine life and waves, which other times of the year affect the long crossing from Puntarenas, Costa Rica. "It's nearly a 400-mile transit from the mainland, and it can be a bitch if the seas are up," says Gilliam. "But summer sometimes produces flat, calm seas that make for a nice crossing. No matter when you go, rainfall can be staggering." If they had to choose between Cocos and the Galapagos, both he and Bantin would pick the former. "The hammerhead sharks, mantas, etc., are in similar populations as the Galapagos, but the water is much warmer and the visibility is better," says Gilliam. "I also think you have a superior selection of liveaboard vessels, and far less chance of government interference that can cancel trips. Cocos is probably the best place in the world for reliable encounters with large marine life."

Fiji. July to November brings cooler water in the low- to mid-70s, as opposed to the 80-plus-degree water in other months. Two buddies and I scheduled an October trip to Taveuni a few years back, and one buddy found the water too cool for his 3mm, so he called a shop in Nadi to order a 5mm wetsuit, as well as a vest and hood, which was flown over the following day.

French Polynesia. Forget Tahiti or Bora Bora. The best diving is in the Tuamotus islands of Rangiroa and Fakarava (see our June 2007 issue for a full report on diving at both sites). The best conditions will be found during their winter (our summer), when there is less rain, less humidity, and more pleasant temperatures.

Solomon Islands. Gilliam's best experiences there have been between August and October due to placid seas, comfortable temps, little rain and great visibility. "There's a good reason why excellent liveaboards like the Bilikiki shut down from about November to March. And because most flight gateways take you through Sydney and Brisbane, you should take advantage of visiting Australia during its late spring and summer season. "Hey, you're going about 12,000 miles or so . . . stick around a bit and take advantage," Gilliam says.

The Indian Ocean

Indonesia. The huge country straddles a vast area. Pulau Weh near Banda Aceh in the West is a long way from the Bird's Head Peninsula of West Papua in the East. Most of the islands form a natural barrier between the Indian Ocean and smaller seas to their north, and throw in the prevailing monsoon cycles, and you have marked differences in conditions. In the northeast, visits to Raja Ampat and further south in the Banda Sea will be best from late December into late March, Gilliam says. "After that, the wind typically reverses, rain and humidity accelerate, and some areas are inaccessible." Don't even think about visiting southern regions like the Komodo Islands until the seasonal change sets in from June to September, he says. "Then you'll usually get calmer seas, markedly dry conditions without the drenching rains, great visibility, and much warmer water temps. I was at Rinca Island in the lower Komodos in May 2002, and the water temperatures were in the low 50s -- freaking freezing. A month later, I visited again and the temperatures had soared back into the mid-60s, still chilly but bearable. This is due to being in the Indian Ocean, not the South Pacific, and the seasonal effects are more pronounced. Only 10 miles north and back in the Pacific region of the Komodos, you can experience remarkably warmer water and better visibility."

Maurine Shimlock, on the other hand, prefers diving the southern areas of Komodo between December and March, "when the water is warmer and more clear. The northern parts of the park are best dived from June through September for warm water and good visibility." She and Burt Jones, her husband and fellow underwater photographer, regularly run underwater photography trips in the area, and "because guests like to dive both areas of Komodo, we try to plan our trips during the 'swing' seasons of April-May and late September-October for sites in the north and south."

The Maldives. While they're idyllic tropical islands in the middle of the Indian Ocean, they're not always so idyllic, says Bantin. "The seas can be huge and the rain torrential, and that mainly happens from June to December."

Once you get into the Indo-Pacific, you must deal with the dramatic seasonal switches in rain and humidity, and the Ring of Fire threats of volcanic eruptions and earthquakes. But Indonesia, the Solomons and other far-flung places are where the best diving is, according to our expert contributors. "Many of the pelagic species have simply gone missing, and divers need to travel to places like Cocos, Fiji and French Polynesia to see the great schools of fishes that were once common elsewhere," says Bantin.

If you're going on a bucket-list dive trip, double-check with a dive travel expert about the best time to visit, says Shimlock, "A good tour leader or travel agent should be able to advise you on the best times for the best weather in whatever region you want to dive." If you've already booked reservations and bad weather comes calling, don't blame the tour operator for canceled dives or itinerary changes, she says. "The weather is changing everywhere, and most operators have statements in their releases and liability forms stating that they are not responsible for the weather, and they may have to change itineraries because of the weather, etc. If so, realize that the dive operators and trip leaders are changing the route in your best interest, and they're going to try to salvage the trip despite bad conditions."

- - Ben Davison