Sikkim is the wettest part of the north eastern region, the climate varies from the Sub-tropical to the Alpine depending upon the altitude. (Sub-tropical upto 1500 meters: Temperate-1500-2000 meters; Alpine upto 4000 meters; snowline at 5000 meters and above). The relative humidity remains above 70 per cent throughout the year at most places. The temperature varies with altitude and the slope (generally 6 degree to 10 degree). There are two maximum rainfall areas viz. (i) in South-East which includes Mangan, Singhik, Dikchu, Gangtok, Kerporang, Rongali, Gnathang etc. and (ii) in South-West corner including Hilley. In between these two regions, there is a low rainfall region e.g. at Namchi, where the rainfall is about half of former areas. This is an area in North-West Sikkim which gets very little rainfall (even less than 4.9 mm) as this area is mainly having snow-covered mountaneous.