The desert decides. From October through April the climate is comfortable, with daytime temperatures in the 20s Celsius and cold clear nights — this is when to come for the camel treks and the dunes. November and February are the sweet spot.
May to September is brutal. Daytime highs sit above 40°C, can push past 45°C in July and August, and walking outside between noon and four in the afternoon is genuinely unpleasant. If you are passing through in summer, plan to do everything in the early morning and late evening, and find a pool.
The biggest event of the year is the Moussem of Moulay Abdelkader Jilali, a religious festival drawing pilgrims from across the Draa, traditionally held in the Islamic month of Sha'ban — the date shifts each year, so check locally.