Ouidah is tropical and hot year-round, with daytime temperatures of 28–33°C. The main dry season, November to February, is the most comfortable: cooler nights, drier air, and the Harmattan wind that occasionally fills the sky with Saharan dust. A shorter dry spell in July–August is also bearable.
The rainy seasons — late March to mid-July, and September to October — bring afternoon downpours that briefly turn the red-earth streets to mud, but rarely last all day.
The single best date to be here is 10 January, the Fête du Vodun (National Vodun Day). Practitioners come from across Benin and the diaspora — Haiti, Cuba, Brazil, the American South — for ceremonies, drumming, animal sacrifices, and processions to the Door of No Return. It is the most intense and crowded time, and one of the few cultural events in West Africa where a foreign visitor is genuinely an outsider observing something authentic rather than performed.