Essaouira is comfortable year-round but the weather is unusual for Morocco: the strong north-east alizé wind blows from spring through autumn, keeping summer temperatures mild (often a chilly 22°C when Marrakech is roasting at 40°C) and feeding the surf and windsurf scenes. April to October is windsurfing season; the calmest water and warmest weather come in late September and early October.
The big event is the Gnaoua World Music Festival, held over four days in mid- to late June. Free outdoor stages around the medina host Gnaoua masters — descendants of sub-Saharan slaves whose hypnotic, trance-inducing music is built on hammered metal castanets (qraqeb) and the three-stringed gimbri — alongside jazz, world, and African artists invited to jam with them. Hundreds of thousands of people pack into town; book accommodation months in advance.
Winter (November to February) is mild and sunny, with the wind dropping enough for the town to feel quiet. Bring a fleece for the evenings — the Atlantic damp is real.