The largest state in India, Rajasthan's climate can be divided into four seasons i.e. summer, monsoon, post-monsoon and winter. Temperatures vary depending on the season and the region you plan to visit, but by and large you can visit the state any time of year and find something new to do each time.
Summers in Rajasthan last from April to June and are particularly harsh with temperatures rising up to 48°C during the day. That being said, if you do plan to visit Rajasthan in the summer, head to places like Mount Abu, Kumbhalgarh or Ranakpur. The weather here is pleasant and the views offered are breath-taking. For other cities, the weather is optimal in the early evenings for roaming around outside in the early mornings and late evenings, and it is advisable to stay indoors otherwise.
Monsoon is a far more pleasant experience, the temperatures tend to drop across the state and the rain showers transform the arid landscape of Rajasthan. July to September is a particularly good time to visit if you wish to avoid the crowds you'd usually find during peak tourist season. Bundi, the lake city of Udaipur and the Keoladeo National Park are picturesque and are a must visit if you plan to travel to Rajasthan during the Monsoon.
Winter-The temperatures continue to drop once the monsoon has passed, and come October winter sets in that lasts till March. During December and January, there can be a severe variation in temperatures during the day and the night. In fact, temperatures are known to drop as low as 0°C and below. This is the best time to visit Rajasthan as the desert sun is not as intense and the days are pleasant. Most of the festivals held in winter are planned as tourist attractions, with visitors coming in from different parts of the world.