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Welcome to the The Government of Timor-Leste
Portuguese Tetum
Welcome to the The Government of Timor-Leste

Travel Guide: Timor - Leste

The climate

Situated in the equatorial regions, Timor presents two annual seasons determined by the monsoon regime. The accidented of the relief, direction of the mountains and proximity to Australia produces different meteorological features among the distinct regions of the small island. Classical climatic classifications, because less apropriate to study the isothermal climates of Indonesia, have been substituted by others soly based on the rainfall records, of which we have adopted Schmidt and Ferguson's.

General aspects

Three climatic zones.

In the tropic regions, where lies Timor, differences of temperature are relatively small, so it's the pluviometric regime that determines the vegetation, the kind of meteorization of the soil and consequently the possibilities of culture and the proper extension of human settlements.

Timor, due to it's accidented relief, direction of the mountains and proximity to the Australian continent, the meteorological circumstances of the island's distinct regions are variegated.

F. A. Soares attended to annual precipitation, average temperature and specially altitude and pluviometrical quotients to climatically divide East Timor into three zones. In the north, the area from the coast to the 600 m bench mark, very accidented, featuring an annual average of temperature over 24 deg., weak precipitation (below 1500 mm annually), and with a very pronounced dry period lasting five months. The mountainous zone is comprised between the northern and southern, above the 600 m level, with temperatures under 24 deg., high precipitation, superior to 1500 mm and a dry period of four months. Finally, the southern zone, which stretches from the coast to the 600 m mark, the relief less accidented, having plains with great extension, exposed to the winds of Australia, much more rainy than the northern zone, with average temperatures generally higher than 24 deg. and a dry period of three months.

The monsoons.

Situated in the equatorial region, Timor presents two annual seasons determined by the monsoon regime, which are more defined than those of the large islands of the Indian archipelago because of it's proximity to Australia.

The winds that blow from northeast (northwest or wet monsoon), from November to May, carry thunderstorms and great rainfalls whilst the moderate winds of Australia, fresh and almost dry, bring little rain and lower the temperature mainly during the night. It's the southeast or dry monsoon.

Nevertheless, between one and the other differences in temperature are almost insensible.

Altitude influences precipitation since its higher as we move to the inland. Distribution of rainfall is conditioned by orographic causes -- such as nature and disposition of the relief -- and distance of the sea.

The southern zone adds much higher precipitation in comparison with the northern what seems strange at first, not only because of the monsoon mechanism but also because of her higher latitude and lower temperature. In fact the north is more exposed to the NW (wet) monsoon and the southern to the SE (dry) monsoon. What happens is that Timor is only 500 km far from the Australian continent and as it's longitudinal axis is practically perpendicular to the SW monsoon, the dry winds coming from Australia attain humidity while crossing the Timor sea, that is lost through strong precipitation when touching land and increasingly as leaping the central chain, to arrive at the northern side almost dry. Besides, the southern zone has more extent plains, covered with abundant vegetation, where therefore the absolute humidity is higher.

During the NW monsoon, the masses of moistured air brought by the maritime winds, after a great passage above the islands of the Indonesian archipelago -- very accidented and with great altitudes -- will loose humidity and be forced to rise. As a result, precipitation over Timor shall only happen where these masses of air are subject to higher altitudes: the north receives minor rainfall which increases as reaching the central crest and comes upon the southern zone.

In the northern zone, the humid period, of five months lasts from December to April and the dry period, also during five months, goes form June to October. Transition occurs in April. In the mountainous zone, the humid period (five months) begins in December and ends in April, while the dry period (four months) is comprised between July and October. May and June is the period of transition. The southern zone has a humid period of seven months, from December to June alternated with a dry period of three months: August, September and October. July is the transition month. In all three zones, November marks the transition between the humid and dry periods.

Pluvial regime.

The annual quantity of precipitation is exceptionally high in the humid period and opposite in the dry period. Amongst the three zones, the northern lands are responsible for the highest variations in the values of the pluviometric quotient (quota with which every month contributes for the total precipitation of a year) whilst the southern zone is the most homogenous.

Annual frequency rates are low in general terms, the lowest in the northern zone and less lower in the mountainous zone. During the humid period rates are relatively low considering that 80% of annual precipitation falls during that time. There can be found a maximum of 61 days in a hundred at Maubisse and Atsabe (mountainous zone) and a minim of 23 in Manatuto (northern zone). In the dry period, decrease is parallel. While in Central Europe and cereal regions of North America there's to be expected forty days with rain, in East Timor not more than eleven in a hundred are rainy.

As usual in the tropical regions, values of the pluviometric quotient (between the precipitation of a period and the days with rainfall) in Timor are high. More intense raining is to found in the southern zone, and less in the North. The consequences of this are also predictable: heavy showers bring little benefit to the plants as the majority of the water is lost by superficial draining, which on the other hand, will carry out an important role in the process of erosion, depending on the nature of the terrain and topographical conditions. On the contrary, when rainfall intensity is weak, most of the water infiltrates and is retained in the soil, becoming part of it's economy.

The temperature.

In Timor, the annual average, diversely to the precipitation, stands very regular. During the NW monsoon, we can better sense the heat, as there's no wind blown from the land which in the SE monsoon refreshes the constancy of temperature, mainly during the night.

In the torrid zone, duration of days and nights and meridian heights of the sun suffer small variations, and this way, differences between monthly temperature averages are low. This isothermal feature perfectly embodies Timor in the Indonesian archipelago, where the most notable factor and with increased influence in the types of climates is precipitation.

Naturally the northern and southern regions are hotter than the mountainous, as temperature falls with altitude. Absolute differences leap up to less than 10 deg. in the most. In view of the very accidented relief of the territory, one often comes across rapid changes just a few minutes drive if ascending some hundred meters, like between Díli and Dare (with a 4 or 5 deg. difference).

If we are to calculate the deviations on the average temperatures of the months in relation with the annual references of the many regions, it's liable to distinguish a hot and a cold period. The first lasts between November and April inclusive (at the time of the NW monsoon) with the deviations being always positive except in Liquiçá, Aileu, Fatu-Bessi and Alas. The cold period (SE monsoon) goes from May to October, generally presenting negative deviations. The coldest month is July and the hottest is November.

Humidity and evaporation.

Humidity of the air is normally higher between December--May, obviously during the NW monsoon. Evaporation is higher in the period of June--November, variating inversely to precipitation, temperature and humidity of the air which are lower. This happens because in the December--April period, (during the NW monsoon), occurs an excess of precipitation over evaporation while a deficit takes place along May--November (SE monsoon).