May is warm, dry and reliably pleasant in Casablanca. Daytime highs reach around 22°C, the ocean breeze keeps the warmth comfortable, and the wet season is over for good — bright, settled days become the norm. It is an ideal time for the seafront: the Corniche, the Ain Diab beach clubs and the vast esplanade around the Hassan II Mosque all come into their own under clear Atlantic skies.
The city sits at a comfortable sweet spot before summer's haze and crowds. A morning inside the mosque, an Art Deco wander through the centre-ville, a seafood lunch by the water and an evening along the Corniche make for an easy, full day in mild, bright weather. The clean coastal light is at its sharpest, and the breeze takes the edge off the midday sun, so sightseeing rarely feels demanding.
May also makes Casablanca an excellent hub for a wider trip. Rabat is an hour up the coast, the imperial cities are at their spring best, and the city's major airport and rail links make arrival and departure easy. For travellers who want warm, dry seafront days with the city's business-and-culture character intact and crowds still modest, May is a confident choice.