Explore historical and projected climate data, climate data by sector, impacts, key vulnerabilities and what adaptation measures are being taken. Explore the overview for a general context of how climate change is affecting Samoa.

Country Summary

This page presents high-level information for Samoa's climate zones and its seasonal cycle for mean temperature and precipitation for the latest climatology, 1991-2020. Climate zone classifications in the map below use observed, historical data (sourced from the Climate Research Unit [CRU]) and are derived by applying the Köppen-Geiger climate classification methodology. This classification divides climate into five primary climate groups, which are divided based on seasonal precipitation and temperature patterns. The five primary groups are A (tropical), B (dry), C (temperate), D (continental), and E (polar). All climates, except for those in the E group are assigned a seasonal precipitation sub-group (second letter). It is important to understand the different climate contexts that exist within a country as well as the surrounding region when analyzing current climates and projected change. Climate classifications are identified by hovering your mouse over the legend. A narrative overview of Samoa's country context and climate is provided following the visualizations.

Köppen-Geiger Climate Classification, 1991-2020
  • Af
  • Am
  • As/Aw
  • BWh
  • BWk
  • BSh
  • BSk
  • Csa
  • Csb
  • Csc
  • Cwa
  • Cwb
  • Cwc
  • Cfa
  • Cfb
  • Cfc
  • Dsa
  • Dsb
  • Dsc
  • Dsd
  • Dwa
  • Dwb
  • Dwc
  • Dwd
  • Dfa
  • Dfb
  • Dfc
  • Dfd
  • ET
  • EF

Located about halfway between Hawai’i and New Zealand, the Independent State of Samoa is a small island country in the southwest Pacific. Samoa is of volcanic origin with a total land area of about 2,900 square kilometers (km2) across 4 main inhabited islands and six uninhabited islands. The main islands are characterized by a rugged and mountainous topography, with some peaks rising more than 1,000 meters (m) above sea level – its highest peak is Mt Silisili, at 1,858 meters, on the island of Savai’i. Although there has been much forest depletion on some of the islands, more than 1,700 km2 are categorized as forest areas; around 46% of Upolu and 69% of Savai’i’s total land area is covered by lush vegetation and rainforest. Samoa’s climate is characterized by high rainfall and humidity, near-uniform temperatures throughout the year with slight seasonal variation, winds dominated by the south-easterly trade winds, and the occurrence of tropical cyclones during the southern-hemisphere summer. Samoa has two seasons, marked by significant differences in rainfall. The annual rainfall is about 3,000 millimeters (mm) (varying from 2,500 mm in the northwest parts of the main islands to over 6,000 mm in the highlands of Savai’i), and about 75% of the precipitation occurs between November and February. There are commonly tropical cyclones during Samoa’s wet season, particularly between December and February. Samoa is also vulnerable to anomalously long dry spells that coincide with the El Niño Southern Oscillation (ENSO). As of 2019, Samoa had a population of nearly 197,100 people. The population growth rate is affected by significant levels of emigration, which has been evident since Samoa’s independence in 1962 and is partly attributed to the New Zealand quota scheme of 1,100 people, and annual seasonal employment opportunities.

Samoa is located within a region in the Pacific that is known for the frequent occurrence of tropical cyclones, which bring damaging winds, rains and storm surge especially during the period October to May; GDP growth rates in Samoa have been notably affected by external shocks over the past few years. Primary industries such as agriculture and fisheries underperformed in 2018 likely due to changing weather conditions and the cyclone which struck the country in February 2018, causing extensive damage to crops and prevented some of the large fishing vessels from going out to sea. Storm events have historically affected the islands, with 1990 and 1991’s Cyclones Ofa and Val, and 2012’s Evan, collectively contributing an estimated US$611 million in economic damages. With approximately 70% of Samoa’s population and infrastructure located in low-lying coastal areas, projected sea level rise could exacerbate coastal erosion, loss of land and property, and dislocation.