Seasons and climate
Visit the islands of Tahiti, get sun throughout the year !
French Polynesia is a tropical destination with lots of sun and just enough rain for its luxuriant vegetation and its colorful flowers.
It receives in average 2,500 to 2,900 of sunshine per year. (ie : 8 hours of sun per day). Temperatures range between 24°C and 30°C all year through and lagoonwater temperature varies between 23°C and 26°C.
Thus, the climate of Polynesia -defined as marine tropical- is hot (average air temperature is 26.5°C) and humid (hygrometry : 75%) but tempered by the ocean. Thus, Polynesia is submitted to northeast and southeast trade winds converging to the equatorial zone which create 2 distinguished seasons : the dry season and the humid season.
- The dry season -also called Austral winter- taking place between April and October brings an expected coolness, July and August being the coolest months of the year due to southeast trade winds calledmaraamu. As a consequence a cotton sweater will often be enjoyable in the evening (or early in the morning).
- The humid season -also called Rainy season- starts in November and ends in March. It brings mugginess, humidity as well as heavier and more frequent rains than in the dry season. During that season, tropical storms may occur. Winds can reach speeds of over 220 km/h and can eventually evolve to a cyclone, an extremely rare event though. French Polynesia was touched lastly by cyclones at the beginning of the 90’s after having been hit 6 consecutives times in 1982-1983 (this had not happen since 1906 !). These cyclonic events are due to a well know phenomenon called “El Nino” (see below for more details).
Yearly average data in Tahiti
Located in an inter-tropical zone, French Polynesia presents a certain climatic unity. However, as French Polynesia is spread on a surface as large as Europe, the climate will change slighly from one archipelago to the other. In the Austral archipelago (south) that includes some islands located south of the Capricorn tropic, the climate is more tempered and low temperatures can reach 10°C during the dry season. In the Marquesas islands (north), the dry season occurs between August and December. Due to a lack of relief, the Tuamotu archipelago (east) receives less rainfalls than the others as the clouds don’t encounter mountains to stop them.
Finally, high islands (such as Tahiti, Moorea or Bora Bora) feature micro-climates related to their altitudes and exposition. Eastern coasts are more exposed to trade winds and consequently receive more rainfalls than the western coasts that are more sheltered.
This phenomenon has been studied by meteorologists for many years and it is well-known for its unpleasant consequences and more specifically for its role in the development of cyclones and hurricanes.
Actually, El Nino is a periodical marine draft whose activity is not considered abnormal since it has been active for the past 5,000 years. What is abnormal is its high frequency in the latest years. It usually appears around Christmas time (that is why it has been named El Nino – the Child). It occurred in 1972/73, 1975/76, 1982/83, 1986/87, 1991/92 and 1997/98 (the strongest of the century). Using the effects of trade winds, El Ninois responsible for bringing down along the coasts – from western to eastern Pacific – hot waters of equatorial regions.
Normally, trade winds make high pressure subtropical air to converge towards equatorial low pressure regions, drawing along with them hot ocean waters from East to West. But when those trade winds weaken, they reverse (change round) and consequently they draw with them those same hot water from West to East. This constitutes el phenomenon called “El Nino”.
In eastern Pacific, water temperatures are usually below 25°C. Those hot water currents make the average ocean water temperatures to increase by 3 to 4°C. This increase generates a succession of climatic anomalies, characterized in Polynesia by trade winds inversion and sometimes the birth of a cyclone when the ocean temperatures is over 28°C.
El Nino is only a small part of a more global climatic fluctuation system called E.N.S.O. ( El Nino Southern Oscillation). The research program TOGA (measurements of atmospheric air pressures taken in the regions of Darwin – North of Australia – and Tahiti) associated with TOPEX-POSEIDON and JASON 1 programs (*) made it possible to understand and detect this phenomenon. Pressure differences between Tahiti and Darwin constitute a good indicator of El Nino phenomenon.
(*) JASON 1 : satellite program measuring the sea-level altitude at 500,000 different points on the earth.