Sinharaja forest cover receives between 3000-6000 mm of rain throughout the year and have a minimum rainfall of over 200 mm even during non monsoon periods. The mean temperature is between 18-27 degrees Celsius with a humidity of 75% - 90%. Only a faint sunshine reaches the ground layer of the forest which ranges from 5% - 15% of the total sun light. The land coverage of the Sinharaja Forest is 21 kM lengthwise, with a minimum width of 3 kM and a maximum width of 7 kM throughout that land extent. The location of Sinharaja rain Forest is between 6 D 21 M and 6 D 27 M , North and 80 D 25 M and 80 D 34 M, East. Gin Ganga and Kalu Ganga [ Rivers Gin and Kalu] gets its water flow from this forest land. The highest elevated mountain peak found at Sinharaja is 1170 Mts and has eight peaks over 600 Mts.
Sinharaja Rain Forest is home to numerous indigenous birds such asthe Ceylon Hanging Parrot (Loriculusberyllinus), the Ceylon Grey Hornbill (Ocycerosgingalensis), the Ashy-headed Laughing Thrush (Garrulaxcinereifrons), Layard’s parakeet (Psittaculacalthripae), the Jungle fowl (Gallus lafayetii ), the Spur fowl (Galloperdixbicalcarata), the Ceylon Wood Pigeon (Columba torringtonii), the Brown- capped Babbler (Pellorneumfuscocapillum), the Red-faced Malkoha (Phaenicophaeuspyrrhocephalus) and the Ceylon Blue Magpie (Urocissa ornate) among others, are prominent in this area.