Flooding from heavy rainfall along with cyclonic storms occurs every four or five years in the country. There have been numerous events within recent years which demonstrate flood prone areas and areas susceptible to flood related damage. The historical rainfall data show a decreasing trend in the annual and wet season rainfall; however, there is ambiguity around rainfall projections due to inconsistencies in models. Even with the uncertainties, majority of the projections suggest a decline in dry season rainfall and an increase wet season rainfall by 2090.
In 2016, during the dry season, Tonga was hit by heavy rains, which caused flooding in the capital. At the Fua’amotu airport, 273 mm of rain was reported which is the highest it has been in the last three decades. The rainfall was accompanied by strong winds that uprooted trees and damaged powerlines, leading to power outages throughout the western part of Tongatapu. Floods in the past disrupted many livelihoods by damaging critical infrastructure and blocking roads.