The Lamu archipelago has two distinct seasons. The kaskazi (December to March) brings the northeast monsoon — hot, dry days, mostly clear skies, calm seas, and easy dhow sailing. This is peak season and the busiest time, especially around New Year.
The kusi (June to September) is the southwest monsoon — cooler air, choppier water, and a stretch of windier afternoons that make beach time less pleasant but sailing exciting. April, May, and November are the long-rains shoulder, when accommodation prices drop sharply and the island is at its quietest.
The single best date to visit is the Maulidi festival in the third Islamic month — a week of qaswida singing, dhow races, donkey races, and processions through the streets. Dates shift with the Islamic calendar; check before booking.