Tenwek is located 240 Kilometers (150 miles) from Nairobi in the Bomet District of Kenya’s Rift Valley Province. The hospital itself is located aproximately 7 km NE from the town of Bomet.
Tenwek is situated in the Western highlands at 6,800 feet, the climate is very moderate and pleasant. September-May is the driest and hottest season; June-August is more moderate and cool in the evenings. Temperatures average between 51 F and 70 F in the cool season and between 52 F and 79 F degrees in the warm season. There are two rainy seasons: November-December and March-June. The average rainfall at Tenwek is 55 inches.