Scuba Diving Seasons in Tonga
Unlike many places in the world, Tonga doesn’t have a “bad” time to scuba dive. The visibility is pretty darn good all year round, averaging around 30m (100ft) in both summer and winter. However, if you are chasing whales, looking to escape the crowds, or just want the conditions a little bit clearer, warmer or whatever, then there will be a best time to scuba dive in Tonga for you. Get more advice on the Tonga diving seasons in the guide below.
Quick Facts About Scuba Diving in Tonga
- The water temperature in Tonga is 21-28ºC (69.8-82.4ºF) year-round for comfortable diving
- The visibility is rarely less than 20m (65ft) but more commonly 30m+ (100ft)
- Be sure to book dive tours well in advance during the whale season (July to October) as some dive operators are also busy running whale swimming tours at this time
- Tonga has an array of amazing dive sites, which you can check out in the 10 Best Dive Sites in Tonga
- Sights on dives can include sharks, tuna and manta rays around 1,500 species of fish and 700 species of coral.
For more tips and facts, head over to the 6 Tonga Scuba Diving Tips.
Winter Diving in Tonga
Tonga’s winter season, also known as the dry season, runs between May and November. However, winter in Tonga is far from “wintery” with sea temperatures typically around 21°C (69°F) and air temperatures between 19 and 29°C (66-84°F). A 5mm full-length wetsuit is usually comfortable for these winter months, along with a warm layer for boat rides after getting out of the water.
The winter gets its “dry season” name due to the less precipitation that the South Pacific receives during the months of May and November. The average rainfall is around 110mm (3.9″) per month and sees lees surface run-off into the ocean. This often results in some of the clearest waters Tonga experiences, often being 30m+ (100ft) up to as much as 70m on some occasions!
If your goal is to swim with humpback whales, then the winter season is the best time to try scuba diving in Tonga. Whales can only be found in Tonga’s waters between July and October (with a little more of an extended season in Tongatapu and ‘Eua). Learn more about the whales in Tonga in The Guide to Whale Swimming in Tonga.
Finally, another advantage of diving in the winter season is that all of the dive operators are open. Some operators, especially in Vava’u, are known to close shop for the summer, giving you fewer options. Compare dive operators in the 9 Best Scuba Diving Tours in Tonga.
Summer Diving in Tonga
Summer in Tonga runs from December to April and is also known as the wet season. This time is usually hotter and more humid in Tonga, making scuba diving a pretty relieving experience from the heat. Sea temperatures are typically around 24°C (75°F), while air temperatures are between 23 and 31°C (74-88°F). A 3mm full-length or a shortie wetsuit is usually suitable for these months.
December to April also falls into the wet season and the cyclone season in the South Pacific, where the average precipitation per month is 210mm (8.3″). As a result, these months tend to have slightly less water visibility, but still averages around 30m and rarely dropping below 20m.
An advantage of a scuba diving trip in summer in Tonga is that it’s the tourist low season. This means that you can often find yourself in resorts with little to no one around, discounts on accommodations and sometimes even flights, and having entire dive sites to yourself (and your buddy and dive instructor, of course).