The best times to visit Bhaktapur are October to December and February to April — clear skies, comfortable temperatures, and the best chances of seeing the Himalayan peaks to the north from the high points of the old town. The monsoon (June to September) brings heavy rain and humidity but also lush green surroundings and fewer visitors.
Bisket Jatra, held in mid-April at the Nepali new year, is Bhaktapur's most spectacular festival. The main event is the pulling of a massive chariot carrying the image of Bhairavnath through the streets of the old town by teams of men hauling on thick ropes — a genuinely physical and dramatic spectacle that can draw enormous crowds. The chariot is assembled in Taumadhi Square in the days before.
Indra Jatra (late August or September) is a smaller but still atmospheric celebration. The old town fills with oil lamp offerings at shrines throughout the historic centre.
Bhaktapur charges a foreigner entry fee to the Durbar Square area. The ticket also covers Potter's Square and some other sites and is valid for multiple days if you keep the receipt.