Reserve ahead in high season, especially if you’re chugging in on a late-night train. Only better hotels offer heating – bring a sleeping bag if you have one. This is the frontier, and even the best hotels have heaters that fail, hot water that doesn’t work, and electricity that turns off. In the rainy season, prices are slightly lower and it’s not as cold at night. Note that there are water rations in Uyuni year-round. Do not sleep with a propane heater in your room – you can die from the carbon monoxide.