December to February is dry winters for Thimpu with almost no rains until March, with an average of rainfall of just 20 mm, per month. The average goes up to 220 mm in August till 650 mm.
Winter season covers Bhutan from late November up till March, with chill and snowfall all around, going up to 3000 m. The north-east monsoons in winters, extremely fast winds blow all around the high altitudes all through the mountain passes, because of which Bhutan is called Drukyul or the Land of the Thunder Dragon in the local language.