The only sensible months for the Cholistan Desert are November to February. Daytime temperatures sit in the high teens to mid-20s Celsius, nights are crisp, and the desert sand is firm enough for vehicles. The annual Cholistan Jeep Rally in February draws a large crowd to the desert and is worth timing a trip around.
Avoid the summer entirely. Between May and September daytime temperatures regularly exceed 45°C, the road tar melts, and most of the desert sites are effectively inaccessible. The shoulder months of October and March are still hot but tolerable; the monsoon rains in July and August can briefly turn the desert green for a few weeks.