There's a moderate to high risk of Tonga being affected by at least one severe Tropical Cyclone (TC) by the end of the tropical cyclone season for 2025-26, with the peak in the season expected between the months of February to March 2026, says the latest seasonal outlook from Tonga Met released today.

Tonga is expecting an average of two cyclones, including one severe Tropical Cyclone (TC) by the end of the tropical cyclone seasonon 30 April 2026 - although cyclones may still occur outside of the usual TC seasons. The peak in the TC season for Tonga is most likely to occur between the months of February to March 2026. However, cyclones have previously been formed outside of the usual TC season

At the start of the season a total of eight Tropical Disturbances (TDs) developed over the southwestern Pacific region, and only one “TD08F” entered Tonga’s Area of Responsibility. TD08F developed from 30 January to 1 February 2026 and had minimal impact to Tonga.

Tropical cyclone activities in the Pacific Island region, including Tonga are closely associated with the El Niño Southern Oscillation (ENSO), which is the fluctuation and coupling effects of the oceanic and atmospheric conditions between the eastern and western tropical Pacific.

Further updates will be provided by Tonga Met during active cyclone periods to support planning, decision making and preparedness. They urged the public to follow daily forecasts and advisories throughout the TC season.

“All communities should remain alert and prepared throughout the remaining 2025-2026 Tropical Cyclone Season and take heed of tropical cyclone alerts, warnings and advisories seriously whenever it is issued to reduce the negative effects on life and property,” the Meteorology Department of the Ministry of MEIDECC advised.

Marine Heatwave Implications

The severe marine heatwave Tonga experienced on 21 January this year, caused a coupled rise in Tonga’s ocean temperatures of over 3 to 4 degrees and air temperatures over Tongatapu reaching a maximum of 34 degrees.

“The short-term intense heating of the ocean temperatures resulted in dead fish in the coastal waters. This event induced stress on Tongan Marine ecosystems that has been affected by coral bleaching, habitat degradation and reduced coastal fish catch rates,” states the seasonal outlook.

Average rainfall 

The remaining TC season will likely bring average rainfall to all island divisions of Tonga during the remaining cyclone season due to the transitioning from weak La Nina conditions to Neutral for the second half of this tropical cyclone season. In some island divisions, the average monthly rainfall can be breached.

“Any Tropical Cyclones passing close to the country, associated active clouds with heavy rain bands may occasionally affect Tonga with marked high rainfall, damaging to destructive force winds and possible flooding, including sea flooding from storm surge impacts on low‐lying coastal areas,” stated Tonga Met.

The public and important sectors are advised by Tonga Meteorology to prepare:

1. Agriculture: Although there is average cyclone occurrence for Tonga this TC season, strong wind events will happen from time to time and crops remain prone to wind damage. Banana, Papaya and Breadfruit will be affected. At the same time, Neutral to La Nina conditions will bring average to above average rainfall which will be good for planting higher rainfall (big leaf plants) crops such as Kava, Taro, Banana and Kape. Weed management will be a must this season in order to get a good harvest.
2. Water: Water surplus during this season is to be expected for the first half of the TC Season. Therefore, rain water should be collected and harvested this season as much as possible to be used when the rainy season ends around April 2026. Clean roofs and replace guttering.
3. Health: Higher risk of water contamination related diseases occurring due to events of above average rainfall expected and flooding of low-lying areas. Mosquitoes will be a problem from the months of November to December due to higher rainfall and higher humidity so mosquito management will be key to prevent mosquito transmitted disease like dengue.
4. Infrastructure: There is a moderate to high chance of one severe cyclone happening this season, so the public are advised to fix shutters and trim trees near the house just in case we get a severe event.
5. Tourism: Moderate to High risk for Tourism activities due to moderate to high chance of a severe cyclone occurring.
6. Fisheries: Ocean nutrients will be abundant due to weak La Nina to neutral conditions so expect tuna fisheries to be good as well as trolleying. Expect low to moderate coral bleaching or algae blooms.
7. Utilities: Moderate to high risk of Communications, Water and Power utilities failures due to tropical cyclone activity. But high risk of flooding related problems.
8. Transport: Moderate to high risk of above than normal cancellations to ferry and aircraft operations due to stronger winds and tropical cyclone activity. Higher risk road and drainage flooding related problems due to higher expectation of above average rainfall.