 Parmanent rivers include Sondu, Eaka, Kijauri, Kemera, Charachani, Gucha (Kuja), Bisembe, Mogonga, Chirichiro, Ramacha and Egesagane and all of them drain water to lake victoria.County has a temperature range between 10C – 28.7C and Annual rainfall ranges between 1200 mm-2100 mm per annum.long start December to June in and short rain seasons from June and July to November.