Spring (April and May) and autumn (September and October) are the best times to visit Jeonju. Spring brings cherry blossoms to the Hanok Village and the parks around the city, and the Jeonju International Film Festival runs in late April or early May. Autumn turns the trees on the hillsides behind Omokdae gold and red, and the cooler temperatures make walking comfortable.
Summer (June through August) is hot, humid, and rainy during the monsoon season, though the city doesn't empty out entirely — it's a popular domestic destination year-round. Winter can be cold but the Hanok Village remains open, and there is something to be said for having the stone alleyways largely to yourself in January.
The Jeonju International Sori Festival, celebrating traditional Korean and world music, is held in late September or early October.