Climate conditions of SNPBZ are determined by the monsoon. In the summer months (July-August) the advancing summer monsoon clouds penetrate into the Dudh Kosi Valley carrying moisture. The moist clouds are forced to lift by increasingly higher mountain ranges as they advance northwards and precipitate. Seventy to eighty percent of annual precipitation occurs in the summer (June-September) with the remainder of the year being relatively dry and cool. Relative humidity remains at 100 percent even in the upper valleys during monsoon, and humidity rapidly decreases after monsoon. Climate of SNPBZ therefore can be described as generally moist and cool in summer and cold and dry in winter. There are marked variations in temperature and precipitation infl uenced by altitude and seasons. Temperature recorded at Thamo village (3,400 m) showed maximum mid-summer (June and July) temperature remained above 18ºC. The minimum temperature falls to –6ºC in January. Light snow begins to fall in the autumn but winter snow accumulation rarely exceeds 1 meter in the Park and less so in the lower buffer zone area. Gale force winds are common in the higher elevation areas during the winter months. Most days from October to December are bright with sunshine and clear blue sky.