The short answer: October through March. The longer answer depends on what kind of night you are after.
The cool months — October to February
This is when the desert is comfortable. Daytime temperatures sit between 20 °C and 30 °C, and nights can drop to single digits — cold enough for a blanket around the fire to feel genuinely necessary, not staged.
December and January are the coldest, which makes the campfire and the hot chai after the camel safari feel less like amenities and more like relief. These are also the clearest months for stargazing: low humidity, no haze, and a sky so clean the Milky Way is visible without any equipment.
The trade-off: this is also peak season. Jaisalmer gets busier, prices across the region edge up, and the dunes at Sam — though not at Khuri — draw larger crowds at sunset.
March — the shoulder
Still pleasant through mid-March. Temperatures climb but evenings stay cool. The crowds thin noticeably after the Holi weekend, making it a good window for anyone who wants the weather without the peak-season density.
April to June — the heat
Daytime temperatures regularly cross 40 °C and can push past 45 °C in May and June. The desert is genuinely hot — not "warm" — and the experience shifts accordingly. Fewer visitors, which has its own appeal, but the physical comfort of being outdoors through the afternoon and evening is limited.
If you are drawn to the emptiness: some travelers come specifically for this. The dunes are deserted, the light at sunset is extraordinary through the heat shimmer, and the camp runs at a fraction of capacity. But be honest with yourself about heat tolerance before booking.
July to September — the monsoon
Jaisalmer gets very little rain compared to the rest of Rajasthan, but what it gets falls in this window. Roads can become difficult after heavy rain. The desert greens unexpectedly, which is beautiful if you catch it, but logistics are less predictable and some activities may be adjusted day to day.
Timing around the moon
If stargazing matters to you — and for many visitors it is the single most memorable part of the stay — plan around the new moon. A full moon lights the dunes beautifully but washes out the stars. The homepage shows tonight's moon phase and illumination, which makes it easy to pick your dates accordingly.