Tonga Weather, Seasons & Climate + Weather by Month

A Guide to the Weather and Climate in Tonga

When you’re looking to escape to a tropical paradise, the weather is kind of important! Tonga is a tropical island archipelago with two seasons, yet never really experiences cold weather. Regardless, there are significant changes in rainfall and humidity throughout the year. So to answer the question: what is the weather like in Tonga? Check out our guide to the Tonga weather, seasons and climate, as well as what the weather is like month by month!

The Seasons in Tonga

Tonga has a tropical climate with a hot and humid period between November and April and a drier and cooler period between October and May. The seasons are therefore split into the following:

Wet/summer season: November to April
Dry/winter season: May to October

Note that Tonga still experiences rain even during the “dry” season.

Tonga Year-Round Weather: What is the Annual Climate?

Tonga Weather, Seasons & Climate + Weather by Month

The Temperature in Tonga

Tonga experiences warm temperatures all year round due to its position just north of the Tropic of Capricorn and south of the Equator. This means that Tonga’s southern islands experience slightly cooler temperatures than the northern islands. Also due to the country’s position, temperatures only mildly fluctuate throughout the year with the main temperature differences being between the dry season and the wet season.

Tonga Year-Round Temperature: What is the Average Temperature in Tonga?

According to the Tonga Meteorological Service, the average annual temperature for Tonga ranges from 23-28°C (73-82°F), while the mean humidity is around 75%.

The mean annual temperature over southern Tonga (Tongatapu and ‘Eua) is 24°C (81°F), while the mean annual temperature over northern Tonga (Vava’u and The Niuas) is 27°C (70°F).

Scroll down for temperature listings for each month in Tonga.

What is the Hottest Month in Tonga?

The hottest month in Tonga is typically February or March.

Does Tonga Get Cold?

Tonga never really gets “cold” with temperatures rarely dropping below 15°C (59°F). The coldest temperature on record was 8.7°C (47.7°F) on 8 September 1994.

How Hot Does it Get in Tonga?

Summer temperatures in Tonga seldom go above 33°C (91°F). The highest temperature on record in Tonga was 35.5°C (95.9°F) on 1 February 2016 in Niuafo’ou.

The Sea Temperature in Tonga

The temperature of the sea (the water temperature) in Tonga is comfortable for swimming all year round with an average yearly sea temperature of around 26°C (79°F).

The highest sea temperatures tend to be experienced during the wet season with the average temperature being 27.8°C (82°F) between November and April.

The lowest sea temperatures only go down to around 25°C (77°F) during the dry season between May and October.

Again, average sea temperatures month-by-month can be seen in our monthly weather guides below.

Rainfall in Tonga

Don’t be fooled by the labels “dry” and “wet” season. Rainfall can occur all year round in Tonga. The yearly average rainfall amounts to around 2,500 mm (79 in) in northern Tonga and 1,700 mm (67 in) in southern Tonga.

As the name suggests, the wet season is when maximum precipitation occurs – about 60-70% of the annual rainfall – with an average of 186 mm (5.3 in) falling per month between November and April.

In the dry season, Tonga still gets a share of rainy spells with an average of 111 mm (4.4 in) precipitation per month between May and October.

Due to Tonga’s maritime climate and mostly flat terrain, rainy spells come in quick, heavy and often short bursts over the islands.

Which Islands Receive the Least Rain in Tonga?

According to the Tonga Meteorological Service, the central island group of Ha’apai receives the least rainfall in Tonga.

What is the Wettest Month in Tonga?

The wettest month in Tonga is March.

What is the Driest Month in Tonga?

The driest month in Tonga varies between June and July.

Does Tonga Get Snow?

No, Tonga does not get snow.

Daylight and Sunshine Hours in Tonga

Tonga experiences long days all year round with daylight hours spanning 13 hours per day from October to February. In the dry season months, this only drops down to 11 hours with the shortest days being in June.

With the long days comes plenty of sunshine. The most sunshine hours are experienced between November and April, averaging 6 hours per day. While the dry season sunshine hours are barely reduced with an average of 5 sunshine hours per day between May and October.

How Much Sun Does Tonga Get?

Tonga has long days with a lot of sun. Daylight hours range from 10 to 13 hours throughout the year, while the average sunshine reaches 18 sunshine hours in the height of Tonga’s summer (December to March).

Severe Weather Events

Tropical cyclones that develop in the South Pacific have a risk of affecting Tonga. The cyclone season in Tonga and the South Pacific starts in November and ends in April, i.e. during the wet season. The peak months for cyclone risk are the months of December, January and February. There is also a higher risk of cyclone activity during an El Nino year.

Tonga has a history of cyclone activity. The worst cyclones were Cyclone Ian in January 2014 which caused much damage and one death, Cyclone Gita in February 2018 which destroyed some 120 homes, damaged around 1,130 buildings and caused two deaths. This is by no means an all-inclusive list, so check out our month-by-month weather guides for November, December, January, February and March, which include the history of cyclones in Tonga.

Tonga is well-prepared with emergency procedures should a cyclone occur, which you can learn more about in Cyclone Safety in Tonga: How to Prepare for a Cyclone.

Tonga Weather by Month

January Weather in Tonga

The year gets off to a hot and humid start in Tonga, as it is in the midst of the wet season. It’s also the cyclone season in the South Pacific, so it’s best to be aware of cyclone warnings – see our Tonga cyclone guide for more details. Otherwise, the country is vibrant with New Year and Chinese New Year (changeable) celebrations, particularly in Nuku’alofa.

Average temperature: 30°C/86°F in the day, 23°C/74°F at night
Average sea temperature: 28°C/82°F
Average rainfall: 174 mm/6.9 in
Daylight hours: 13 hours

For more in-depth information, see our complete guide to the Tonga Weather in January.

February Weather in Tonga

It’s still the wet season in Tonga, with some of the heaviest rainfall experienced in February. Temperatures are warm and humid, but at least the days are long and there are still plenty of sunshine hours for those seeking some sun. February is also considered the low season, which is a cheap and quiet time to experience the islands. See the 10 Reasons to Travel in the Low Season in Tonga for more benefits.

Average temperature: 31°C/88°F in the day, 24°C/75°F at night
Average sea temperature: 28°C/83°F
Average rainfall: 210 mm/8.3 in
Daylight hours: 13 hours

For more in-depth information, see our complete guide to the Tonga Weather in February.

March Weather in Tonga

The wet season continues, with still the slight risk of cyclones developing. The northern groups of islands, like Vava’u and The Niues, experience their highest rainfall and temperatures of the year, while the middle islands of Ha’apai are not close behind.

Average temperature: 31°C/88°F in the day, 23°C/74°F at night
Average sea temperature: 28°C/83°F
Average rainfall: 206 mm/8.1 in
Daylight hours: 12 hours

For more in-depth information, see the complete guide to the Tonga Weather in March.

April Weather in Tonga

April is the final month of the wet season, still bringing some “April showers” along with it. Temperatures steadily start to cool in the southern islands, such as Tongatapu and ‘Eua. It’s also the last month of the cyclone season. Humidity levels fall also, making it easier to breathe again!

Average temperature: 30°C/86°F in the day, 22°C/69°F at night
Average sea temperature: 28°C/82°F
Average rainfall: 165 mm/6.5 in
Daylight hours: 12 hours

For more in-depth information, see our full guide to the Tonga Weather in April.

May Weather in Tonga

May is the official start to the dry season, where temperatures start to get cooler and the humidity drops. There are fewer rain days but when it does rain, it’s usually heavy showers. The UV levels are also not quite as intense as in summer, averaging around 7 UV index at midday. May is a good time to visit “The Kingdom” before the tourist crowds arrive, while it is also the beginning of the sailing season in Tonga.

Average temperature: 30°C/86°F in the day, 20°C/68°F at night
Average sea temperature: 27°C/80°F
Average rainfall: 111 mm/4.4 in
Daylight hours: 11 hours

For more in-depth information, see our complete guide to the Tonga Weather in May.

June Weather in Tonga

The dry season really kicks into gear with cooler and much drier days than what’s experienced in summer. June 4th is a public holiday, while the end of June is when the first humpback whales can be seen in Tonga’s waters for the calving and mating season. Sea temperatures are also dropping but still warm enough for a comfortable swim. Learn more about the whale season in The Guide to Whale Swimming in Tonga.

Average temperature: 29°C/84°F in the day, 20°C/67°F at night
Average sea temperature: 26°C/78°F
Average rainfall: 95 mm/3.7 in
Daylight hours: 11 hours

For more in-depth information, see the complete guide to the Tonga Weather in June.

July Weather in Tonga

July is a popular time to be in Tonga, with the official start of the whale swimming season, the Heilala Festival at the beginning of the month, and the weather becoming more and more appealing for those wishing to escape the cold winter of their own country. July 4th is a public holiday for the King’s Birthday, while the only other reason shops and services will close down will be for the usual Sunday rules.

Average temperature: 29°C/84°F in the day, 18°C/65°F at night
Average sea temperature: 25°C/76°F
Average rainfall: 95 mm/3.7 in
Daylight hours: 11 hours

For more in-depth information, see the complete guide to the Tonga Weather in July.

August Weather in Tonga

August is one of Tonga’s coolest months, which is still hot enough for travellers to enjoy a tropical and sunny getaway. But you’ll be thankful for bringing a light jacket for the cooler evenings or when darting between the islands by boat. The whale season is still going strong, while snorkelling and scuba diving are also popular things to do at this time of the year.

Average temperature: 29°C/84°F in the day, 18°C/65°F at night
Average sea temperature: 24°C/75°F
Average rainfall: 117 mm/4.6 in
Daylight hours: 11 hours

For more in-depth information, see the complete guide to the Tonga Weather in August.

September Weather in Tonga

September is usually an ideal month for travellers in terms of the weather and the activities available in Tonga. The weather is warm but not too hot, mostly dry with usually 13 days of the month experiencing rain, and the whale season still going. It’s typically a little drier in Vava’u than it is in Tongatapu. September is also an ideal month for fishing in Tonga, while events include the Blue Water Festival, the Prince’s Birthday public holiday, and Faka-Sepitema. Learn more about these events in The Top Events & Festivals in Tonga.

Average temperature: 29°C/84°F in the day, 19°C/66°F at night
Average sea temperature: 24°C/75°F
Average rainfall: 122 mm/4.8 in
Daylight hours: 12 hours

For more in-depth information, see the complete guide to the Tonga Weather in September.

October Weather in Tonga

The whale season comes to an end in October, but it’s still idyllic weather for most travellers. Days are long and mostly dry, especially in the northern islands of Vava’u and the Ha’apai group. The sea temperatures rise slightly, making it a good time for snorkelling and diving.

Average temperature: 29°C/84°F in the day, 20°C/67°F at night
Average sea temperature: 25°C/78°F
Average rainfall: 128 mm/5 in
Daylight hours: 13 hours

For more in-depth information, see the complete guide to the Tonga Weather in October.

November Weather in Tonga

November is the month when you can really feel the transition from the dry season to the wet season in Tonga. Days are getting hotter, it’s starting to get more humid, and the rain gets more frequent towards the end of the month. Nevertheless, it’s the tourist low season so it’s a good time to experience the last of the good weather before the wet season gets into full swing.

Average temperature: 30°C/86°F in the day, 21°C/70°F at night
Average sea temperature: 25°C/78°F
Average rainfall: 123 mm/4.8 in
Daylight hours: 13 hours

For more in-depth information, see the complete guide to the Tonga Weather in November.

December Weather in Tonga

The wet season is well and truly here, where downpours are often heavy but short before the sun comes back out again. Travel schedules between the islands are often cancelled or rescheduled due to bad weather. It’s also the cyclone season, so it’s best to be aware of the cyclone and weather warnings. There are plenty of public holidays where the country shuts down for Christmas and New Year, as well as King Tupou I Commemoration Day on the 7th.

Average temperature: 30°C/86°F in the day, 22°C/73°F at night
Average sea temperature: 27°C/80°F
Average rainfall: 175 mm/6.9 in
Daylight hours: 13 hours

For more in-depth information, see the complete guide to the Tonga Weather in December.

More About What the Weather is Like in Tonga

That’s it for our guide on what the weather is like in Tonga. For more Tonga climate and weather tips, check out the following guides:

Finally, get even more tips for planning the perfect getaway in The Complete Travel Guide to Tonga and the 31 Tips for Travelling in Tonga.

Author

Robin (Lopini) C.

This article was reviewed and published by Robin, the co-founder of Tonga Pocket Guide. He has lived, worked and travelled across 16 different countries before settling in the South Pacific, so he knows a thing or two about planning the perfect trip in this corner of the world. Robin works and consults regularly with the Ministry of Tourism of Tonga. Robin is also the co-founder of several other South Pacific travel guides and is a regular host of webinars with the South Pacific Tourism Organisation.

Contact Robin via our contact page