Kiribati has a hot, humid tropical climate, with air temperatures very closely related to the temperature of the oceans surrounding the small islands and atolls. Across Kiribati the average temperature is relatively contact year round. Changes in the temperature from season to season are no more than about 1 degree Celsius.
The dries and wettest periods in the year vary from location to location. At Tarawa, in the west, the driest six-month period begins in June, with the lowest mean rainfall in October. The wet season usually lasts from around November to April. At Kiritimati, 2000km to the east, the wet season is from January to June (Figure 1).
Rainfall in Kiribati is affected by the movement of the South Pacific Convergence Zone and the Intertropical Convergence Zone. They extend across the South Pacific Ocean from the Solomon Islands to the east of the Cook Island, and across the Pacific just north of the equator, respectively (Figure 2). These bands of heavy rainfall are caused by air rising over warm water where winds converge resulting in thunderstorm activity.
Kiribati’s climate varies considerably from year to year due to the El Nino-Southern Oscillation. This is a natural climate pattern that occur across the tropical Pacific Ocean and affects weather around the world. There are two extreme phases of the El Nino-South Oscillation: El Nino and La Nina. There is also a neutral phase. Across Kiribati, El Nino events tend to bring wetter, warmer conditions than normal. In the wettest years Tarawa has received more than 4000mm, while in the direst years as little as 150mm of rain has fallen.
Information on this page has been sourced on behalf of the Kiribati Meteorology Service and with kind permission from Australian Bureau of Meteorology and CSIRO, 2011.Current and future climate of Kiribati. Visit www.pacificclimatechangescience.