The summer season in Uttarakhand starts in April and lasts till June. During these months, the temperature in the state varies from 15° to 40°. The summer season in Uttarakhand is relatively better than the plains. Evenings are quite soothing and the temperature drops significantly during the night at most of the places. Most of the hill stations you may not have water coolers and Air condition even. You may need to have a blanket in the night.
Due to dense forest area you may expect medium to heavy rains in the mountains. Which drop down the heat and temperature? Therefore it will be more pleasant to travel in monsson. At low land and in valley it might be bit humid. Though all hill stations remain clean, lush green with fresh air.
Due to its variation with geographical condition temperature will be different at high hills and valleys. Above 250 M ASL you may have snow at most of the places and no snow at the valleys. Winter season considered from Oct to March. Perfect to choose your suitable destination of your interest.