Climate
It is difficult to accurately generalize the climate of Bhutanbecause of the variations in elevations and seasons. outhern Bhutanhas a tropical climate with hot humid monsoons. Spring in the higher valleys (mid-March to May) has warm days (20 °C) and cool nights. June marks the beginning of summer when day temperatures warm up to 27 - 29 °C. By July, the rainy season starts and continue till mid-September. The autumn months of September to November are ideal for trekking with clear skies and mild weather. In December temperatures fall, but the days are warm and the clear, azure winter skies serve a striking background to the snow-capped peaks. On a sunny day, temperatures reach about 16-18 ° C. The nights, however, are cold with temperatures falling below freezing.

Annual Average Temperatures of different places are as follows :

CITY Jan/Feb Mar/Apr May/Jun Jul/Aug Sep/Oct Nan/Dec max/min max/min max/min max/min max/min max/min Paro +13  +3 +15  +3 +23  +13 +25  +15 +22  +10 +12  +3 Thimphu +14 0 +16  +6 +22  +14 +27  +17 +20  +13 +16  +1 Punakha +18  +7 +24  +9 +22  +10 +26  +13 +25  +11 +22  +9 Wangdi +17  +7 +24  +11 +28  +18 +29  +20 +26  +17 +22  +7 Trongsa +12  +1 +16  +2 +20  +14 +18  +14 +17  +13 +16  +9 Bum- hang +10  +1 +16  +5 +18  +10 +21  +13 +19  +11 +15  +2 Mongar +23  +10 +27  +11 +30  +20 +35  +22 +30  +18 +25  +8 Trashi- gang +16  +4 +19  +7 +20  +13 +22  +14 +20  +11 +16  +9