Tongans could face drought in the next three months.
And the number of cyclones affecting the islands could double, according to a warning from UN agency ReliefWeb.
ReliefWeb said it was possible drought could spread as a result of the El Niño cycle, which controls weather patterns in the Pacific.
Niuafo’ou and Vava’u were already experiencing drought conditions according to rainfall data collected. About average rainfall was recorded in Niuafo’ou in August, but below average rainfall had been recorded since June.
The UN agency said drought was evolving in Niuatoputapu and rainfall in Ha’apai and Tongatapu had been below average in the last month.
It said special attention should be paid to sectors that could be affected by drought and cyclones, including agriculture and fisheries, health, water resource management and tourism.
The agency said people should save water and protect resource.
The agency said people living in the area from Tongatapu to the Niuas should be watched for water stress conditions which could develop over the next few months.
El Niño is the movement of warm ocean water from the north of Australia to the South American coast along the tropics.
It brings warmer than normal water to the central and eastern tropical Pacific which usually results in changes in weather and climate. El Niño is a natural occurrence and happens about every three to seven years.
The effects of El Niño in Tonga usually include cooler night time temperatures, lower rainfall during the rainy season and increase in the frequency of tropical cyclone occurrence.
El Niño events normally last for around a year but can be shorter or much longer depending on the nature of the event. Tonga is usually affected by one cyclone per year but increases to around two during El Niño.
The worst droughts to be recorded in Tonga in recent history happened during El Niño Years. The 1982-83 and the 1997-98 caused water shortages to a point where water had to be distributed to the islands of Ha’apai and caused food shortages as a result of devastation to Agriculture.
Category 4 cyclone Isaac and category 5 cyclone Ron both occurred during El Niño years.