Boothbay Harbor is a summer destination. July and August are peak season — the harbor is full, the restaurants are open, whale watching runs daily, and Windjammer Days (late June) is the year's biggest event. The weather is pleasant though rarely hot by southern standards: expect highs around 24°C, cool evenings, and the occasional foggy morning that burns off by midday.
Shoulder season (late May, June, and September) is increasingly popular — the crowds are lighter, prices are a bit lower, and the weather is still good. October brings fall foliage, which can be dramatic along the coast. Most businesses close from November through April, and Boothbay Harbor in winter is a very quiet place indeed, though the Gardens Aglow event at the botanical gardens draws visitors in November and December.
Summer accommodation books up weeks in advance; plan early.