The shoulder seasons — May, June, and September — are the sweet spot. The sea is warm enough to swim from late May, the lanes of the centro storico are pleasant in the early evening, and the beaches and restaurants are open without being besieged. October stays mild but quieter still.
July and August are the Italian summer holiday peak. Monopoli is a Bari favourite and the lidos and old-town restaurants fill quickly; prices for rented apartments roughly double. Many of the best places require reservations days in advance.
The biggest local event is the festa della Madonna della Madia on 14 and 15 December, when an icon of the Virgin is honoured with fireworks and a torchlit procession of fishing boats around the old harbour — a strange and beautiful winter sight in a town that is otherwise asleep at that time of year.