Jaipur is vibrant all the time. But March, for alot of cultural activities and festivals like Holi and Rajasthan Day on 30th of March, would be the best time to visit this city.
Jaipur is best to visit during the winters as from late October to March. Summers can be extremely hot for wandering around while the winters in Northern India are pleasant.
The weather is the most crucial factor when deciding to visit Jaipur. Do not consider visiting Jaipur during the long hot summer (March until July) when the daytime maximum temperatures can reach in excess of 45°C. This intense heat combined with the dust and pollution makes Jaipur unbearable and this is the worst season to visit the whole of India. If you do plan to visit Jaipur in the summer always book air-conditioning in hotels is essential and drink plenty of water.