The weather in this city is extreme, which means it can either be really hot or really cold, but never anything else. The summers are extremely hot, which makes it one of the worst times to visit the area because of the intense heat. This makes sightseeing during the summer torture and it should be avoided, unless it is the only time you can get away.
The winter is cold during the day and the temperature drops drastically during the night, which makes the night time a big of a hassle because you need to wrap yourself up properly. However, the monsoon is full of high humidity and hardly any rain, which makes it one of the best times to visit and see the many attractions.
However, the ideal time to visit is between September until February, which is when the end of the monsoons are around and the winter has kicked in. However, the other ideal time to come is when there are festivals, if you are interested in that, otherwise any other time of the year. If you are coming during a festival time make sure to book your transportation and lodging well in advance so that you get a spot.