The climate—both rainfall and temperature—of the Thiririka catchment is closly related to altitude. Rainfall is less than 700 mm/a in lower altitudes, while its annual averages  totals more than 1600 mm at higher altitudes. A bimodal rainfall regime prevailes: There is a long wet season from mid March to end of April and a short wet season in November and December.

According to the system of Koeppen and Geiger, the climate in the catchment is classified as a typical subtropical highland climate (Cfb).