Sheetal, the best time to visit Ladakh would be around June-Aug. By mid-June, the snow starts melting and you can watch all the beautiful lakes in the area. Still, let me divide the months based on conditions in Ladakh: April - May: Snowfall stops, summers begin. Some snowfall-affected roads may still be closed. Max temp:15 degrees, Min temp: -1 degrees June-Aug: Peak tourist season. Expect great sights and heavy crowd. Max temp: 25 degrees, Min temp: 10 degrees Sep-Oct: Snowfall begins, cool waves in the region. Max temp: 14 degrees, Min temp: -1 degrees Nov-Jan: Freezing temperatures, only accessible through flights. Treks and some sights open for tourists. Max temp: 7 degrees, Min temp: -14 degrees Feb-Mar: Likely water and electricity shortage, gradual decline in temperatures.Various monastery festivals are held in this time. Max temp: 5 degrees, Min temp: -11 degrees. Hope this helps. :)
August or September would be suitable to visit Ladakh as its the begining of winter and also does not have much snow that will restrict you from visiting places
September is one of the best time to go to Leh as this time offers some of the best sights of Ladakh and better road conditions (than amid the Monsoons). As the peak season (June-August) is over, now the rates of the hotel are decreased.
The Ladakh temperature during this time is Maximum 21° C, Minimum 5° C. The climate is cool and wonderful chill begins to look in. It in some cases you can find snows amid late September. Get a chance to enjoy the crystal clear water with glimmering sunbeams falling over the surface and making it sparkle.
Also at this time, the road conditions are much better than the usual. At times there can be snowfall which can cause a roadblock.
Visit some of the best parts of this region like the mesmerizing Pangong Lake and enchanting Tso Moriri and get a chance to learn about the culture and the beauty of this region. Also visit the famous monasteries and the stupas here while you pass through the highest motorable road.