Bergamo is a city that can be visited any time of year.  There are events throughout the year, both indoors and outdoors.  If you want to enjoy the piazzas (aperitivo, outdoor meals), it’s best to visit from April through October, because many restaurants and cafes only have indoor seating in the cooler months.  If you visit during the winter, you can still explore the monuments and tuck into cozy cafes and restaurants for a warm meal and hot drink.