Last week, Tonga recorded its second-lowest temperature ever, at 9.3 degrees Celsius.
According to Tonga Meteorological Services, the lowest temperature recorded in the country was 8.7 degrees Celsius in September 1994.
The near-record low temperature was so chilly that residents were walking around with beanies, scarves and puffer jackets.
NIWA meteorologist Ben Noll spoke to RNZ National presenter Jesse Mulligan about what is happening to the normally warm and tropical Pacific.