The climate of Brunei is characterized by largely constant daily mean Temperatures and relative humidities. And low winds speeds except during Storms (Grant, 1984). The most important climatic descriptor is the rainfall Regime. The mean annual rainfall at Semabat is a little over 4,100 mm, And the Batu Apoi Reserve can expect at least as much rain annually. Although Noted for its inconsistency and variability. Two distinctly wet seasons can Usually be identified (400-600+ mm/month).