Things to Do in Tonga in May
May weather, activities, events & insider tips
May Weather in Tonga
Is May Right for You?
Advantages
- Humpback whale watching reaches its absolute peak in May - mothers with calves are still in Tongan waters before their migration south, and you'll see breaching, tail slapping, and heat runs almost daily. Water visibility is typically 20-30 m (65-100 ft), making this the best month for underwater encounters.
- Shoulder season pricing means accommodation costs drop 20-30% compared to July-August peak, and you'll actually get your choice of resorts rather than settling for whatever's available. Flights from Auckland and Sydney also tend to be cheaper mid-May after school holiday rushes end.
- Cooler, drier conditions make this ideal for multi-island exploration - the 20°C (68°F) overnight lows mean you'll sleep comfortably without air conditioning, and daytime temps around 27°C (80°F) are perfect for kayaking, snorkeling, and walking around Nuku'alofa without melting.
- Cyclone season officially ends April 30, so May offers the psychological comfort of being outside the danger window while still catching late-season whale activity. That said, the weather can still be variable with occasional rain systems, but nothing like the February-March intensity.
Considerations
- Those 10 rainy days listed in the data are a bit misleading - May sits in a transitional period where you might get several consecutive overcast days with drizzle rather than the quick tropical downpours of summer. When a weather system settles in, it can linger for 2-3 days and affect boat schedules.
- Trade winds can be inconsistent in May, which means some days have glassy calm seas perfect for whale swimming, while others bring choppy 1-2 m (3-6 ft) swells that cancel tours. You need flexibility in your schedule - don't plan whale encounters for your only available day.
- By late May, whale numbers start declining as they migrate toward Antarctic feeding grounds. If you're coming specifically for whales, early to mid-May is significantly better than the last week of the month when sightings become less predictable.
Best Activities in May
Humpback whale swimming tours in Vava'u
May is genuinely one of the two best months for swimming with humpbacks, alongside September. The water temp hovers around 25°C (77°F) - warm enough for extended snorkeling sessions without a wetsuit, but cool enough that whales are still comfortable. You'll see competitive male groups (heat runs) chasing females, which creates spectacular surface action. The 70% humidity and 27°C (80°F) air temp mean you're comfortable on the boat between encounters. Book licensed operators who follow Tonga's strict approach guidelines - only four swimmers in the water at once, no touching, 10 m (33 ft) minimum distance though whales often approach closer on their terms.
Sea kayaking in the Ha'apai island group
The moderate 20-27°C (68-80°F) temperature range makes May ideal for multi-day kayaking expeditions through Ha'apai's 60-plus islands. You'll paddle 8-15 km (5-9 miles) daily without the oppressive heat of summer, and the variable weather actually works in your favor - overcast days mean less sun exposure during long crossings. The occasional rain system creates dramatic light for photography. Water is calm enough 70-80% of days for safe passage between islands, though you need to be flexible and wait out rough patches. Camp on deserted beaches or stay in village guesthouses.
Snorkeling and diving at 'Eua Island's cliff walls
'Eua's dramatic underwater topography - vertical walls dropping 30-40 m (100-130 ft) straight down - benefits from May's excellent 20-30 m (65-100 ft) visibility. The cooler water temperatures bring nutrient upwellings that attract manta rays, eagle rays, and schools of barracuda. Surface conditions can be variable, so you'll want 3-4 days on 'Eua to ensure you get at least 2 good diving days. The island itself offers spectacular cliff-top hiking through ancient rainforest when seas are too rough for diving. UV index of 8 means you'll burn quickly at the surface, so use reef-safe SPF 50 and wear a rashguard.
Cultural village stays in outer islands
May's cooler evenings make village life more comfortable for visitors not accustomed to tropical heat. You'll sleep under mosquito nets with windows open to 20°C (68°F) breezes rather than tossing in 26°C (79°F) summer nights. This is kava season - the ceremonial drink is consumed nightly in village faikava circles, and as a visitor you'll be invited to participate. May also sees preparation for the June Heilala Festival, so you might witness traditional dance rehearsals and tapa cloth making. The variable weather means more time spent in community activities rather than constant beach days.
Exploring Tongatapu's ancient sites by bicycle
The main island's flat terrain and 27°C (80°F) daytime temps make May perfect for cycling between archaeological sites - the Ha'amonga 'a Maui Trilithon, Captain Cook's landing site, and ancient burial mounds. Start early around 7am to cover 25-35 km (15-22 miles) before midday heat peaks. The 70% humidity is noticeable but not oppressive like summer's 80-85%. Variable weather means you'll want rain gear in your pannier, but those occasional overcast days are actually ideal for all-day riding. Most roads are paved or well-maintained coral, suitable for hybrid bikes.
Offshore fishing for yellowfin tuna and wahoo
May marks the transition period when pelagic fish move through Tongan waters following baitfish migrations. The variable conditions actually concentrate fish along current lines and temperature breaks. Yellowfin tuna in the 15-30 kg (33-66 lb) range and wahoo up to 20 kg (44 lb) are common catches. The moderate seas and cooler temps make full-day offshore trips more comfortable than summer heat. You'll troll 15-30 km (9-19 miles) offshore where water depth drops to 500-1000 m (1,640-3,280 ft). Even non-anglers enjoy these trips for whale sightings and seabird activity.
May Events & Festivals
Preparation period for Heilala Festival
While the actual Heilala Festival happens in late June and early July, May is when you'll see villages across Tonga preparing traditional dance performances, carving competitions, and beauty pageant rehearsals. It's actually more interesting than the festival itself for cultural observers - you'll witness the authentic creative process rather than polished performances. Village halls hold evening rehearsals where visitors are welcome to watch, and you'll see women's groups working on elaborate tapa cloth and pandanus weavings that will be displayed during the festival.