Boulogne is worth visiting year-round, though the weather is what you would expect of the Channel coast — grey and gusty for much of the year, with warm spells in July and August. Summer brings more tourists and longer daylight hours; the beach to the south of town fills on warm weekends. Autumn is the best time for coastal birdwatching at Cap Gris-Nez.
The Herring Festival in November celebrates the traditional beginning of the herring season, with street stalls, smoked fish tastings, and fishing boats dressed with lights. It is a genuine local event, not much commercialised, and coincides with a point in the year when Boulogne is nearly tourist-free.