By Everest Hala
Marine heatwave conditions are intensifying in Tongan waters, after Nuku’alofa experienced its hottest day on record, hitting 34.6 degrees last week. Tonga Meteorological Services warned today that a significant rise in ocean temperatures around Tonga will likely see the marine heatwave conditions persist into February.
They confirmed the record temperature of 34.5 degrees celcius was recorded In Nuku’alofa, at around midday on Thursday 22 January, breaking the air temperature record of 33.5 degrees recorded in Nuku’alofa, on 21 January 2024 and again on 17 January 2025.
Tonga Met said last week’s weather pattern followed a dominance of the northerly warm and calm to light winds, and the persistence of clear skies, which resulted to the high temperatures recorded over Tonga, specifically in the Nuku'alofa area. Together with the severe marine heatwave conditions present in our waters the sea surface temperature also contributed to our high air temperatures.
Anomaly of +3 °C in Tonga waters
“On 21 January, satellite monitoring recorded a sea surface temperature anomaly of +3 °C in Tonga waters — well above the seasonal average. This sharp increase may be linked to recent reports of dead fish, indicating potential stress on marine ecosystems.
“Importantly, these ocean changes are occurring alongside record-high air temperatures recorded on land across Tonga. The combination of hotter land temperatures and warmer seas intensifies the stress on both marine and coastal environments, increasing risks to fisheries, coral reefs, and community livelihoods,” Tonga Met advised in a statement yesterday
February Marine Heatwave
The Director for Tonga Meteorological Services, Laitia Fifita told Matangi Tonga today that they forecast the heatwave will continue into February.
"We are expecting a moderate to severe marine heatwave conditions to persist over our Tongan waters. It is also important to note that daily and weekly variations may lead to higher-than-expected impacts."
This marine heatwave can cause coral bleaching due to the unfavorable hot ocean teamperature.
Laitia said that this marine heatwave is a factor contributing to Tropical Cyclones.
