Bayeux is at its best in late spring and early summer. June is the most historically resonant month — D-Day anniversary events on 6 June bring commemorations to the beaches and the town, and the Norman countryside is at its greenest. July and August are the peak tourist months; the tapestry museum gets crowded and accommodation books up.
September and October are excellent: crowds thin, the Norman orchards are heavy with apples for cider-making, and the light is beautiful. Spring (April–May) is also good — quieter, green, and cool.
Winter is quiet and the beaches are bleak and windswept, which has its own kind of power at the D-Day sites.