Tanzania is the largest country in East Africa. It is situated south of the equator between 1° and 12°S. It has a long coastline on the Indian Ocean. It is bordered by Kenya and Uganda on the north, by Mozambique, Malawi, and Zambia on the south and by the Democratic Republic of Congo on the west.
There is a fairly narrow coastal plain in the east, but most of the interior consists of a plateau 900-1,500 m/3,000-5,000 ft above sea level. There are a number of mountain ranges which rise to between 2,100-3,000 m/7,000-10,000 ft. In the north of the country the isolated peak of Mount Kilimanjaro, the highest mountain in Africa, rises to nearly 6,000 m/20,000 ft. It has a permanent snow-cap and small glaciers.
The whole country, except the higher mountains, has a tropical climate, but above 3,000 ft this is modified by a significant reduction of temperature, particularly at night. Compare the higher temperatures recorded on the coast at Dar es Salaam with those for Dodoma in the central plateau.
Minimum temperatures and daytime humidity are much lower at Dodoma and cause the climate to be less enervating.
The coastal regions, including the large offshore islands of Pemba and Zanzibar, have heavier and more reliable rainfall than most of the inland areas. Average annual rainfall is almost everywhere above 1,000 mm/40 in on the coast and up to 1,500 mm/60 in in the wetter places.
This compares with an annual fall of between 500-1,000 mm /20-40 in over most of the interior. Only the higher mountain areas receive more rain than the coastal region. The annual rainfall inland is notoriously unreliable and much of it is very sporadic in both time and place.
Rainfall increases a little, and also becomes more reliable, towards the west and around the shores of the three great lakes which are partly included within the boundaries of Tanzania: lakes Victoria, Tanganyika, and Malawi (see the table for Kigoma on Lake Tanganyika).
Over most of the country there is a single rainy season with the heaviest falls between November and April; the period May to October is dry and sunny. The coastal region is rather an exception in that it gets some rain in all months, with the main rain falling between March and May.
The southern coastal district is occasionally affected by heavy rain and strong winds associated with tropical cyclones in the south Indian Ocean.
Although weather on the coast is often rather oppressive because of the higher temperatures, particularly at night, and the high humidity, conditions here are not persistently uncomfortable thanks to regular daily sea breezes. Inland, the lower humidity and cooler night temperatures mean that heat stress is rare although daytime temperatures are quite high and sunshine abundant.
Much of Tanzania has a very sunny climate with many places averaging from seven to ten hours of sunshine a day with fewer hours during the rainy season. As in most other tropical countries the year is usually divided into the rainy and dry seasons, since the terms winter and summer have little meaning in respect of temperature.
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