Grado is at its busiest in July and August, when Italian families fill the beach hotels and the temperature is reliably in the high 20s and low 30s with a sea-warmed humidity. June and September are easier — quieter, warm enough for swimming, and the lagoon bird-life is more visible.
The Perdòn de Barbana, the great floating Marian procession across the lagoon, takes place on the first Sunday of July and is an extraordinary spectacle if you can be here for it. The autumn Boreto alla Graisana food festival celebrates the local fish stew with set menus across the town's restaurants. Winters are cool, often misty, and most beach facilities close — though the centro storico stays atmospheric and the thermal baths run all year.