The weather in Leh tends to be extremely arid, with only 90mm of rain annually, and cold. There are only two main seasons in Leh: summer (March to September) and winter (October to February). The early summer months, up to May, are very hot and dry with temperatures usually hovering around 33 °C and sometimes as high as 40 °C. Winter temperatures are consistently below 0 °C and there is infrequent snowfall.
Leh, the state of Jammu and Kashmir, India, experiences a cold desert climate that features harsh and long winter.

Winter :

Leh goes through a long winter season, from October till March, with the average minimum temperature of -7°C. January is the coldest month of the year when temperature falls below -15°C. Among the winter months October remains warmer with average high of 14°C. Moreover, during this time Leh gets occasional snowfall which makes the climate colder and somewhat unbearable for the tourists.

Summer :

However, the remaining months of the year remain much comfortable for the visitors. Summer, from April till September, sees around 30°C of average temperature while July with more than 33°C of temperature and 15mm of precipitation remains both hottest and wettest. On the other hand, the average low fluctuates between 14-18°C during this time. It is the best time to visit Leh, the second largest district in the country.