Condensation requires energy input, or a considerable change in temperature.
Hot air can hold a lot of moisture, cold air can hold less. Water condenses on surfaces when the air cools down to the point that air would have to carry more water than it can at the new temperature.
Problem with that: it only works great in very humid areas. If you're in a desert, and have 10% humidity, you have to cool down your air by a lot for it to become too saturated and condensation to happen. Not enough cooling, and the moisture stays in the air.
> If you're in a desert, and have 10% humidity, you have to cool down your air by a lot for it to become too saturated and condensation to happen.
Deserts tend to have pretty wild temperature swings. They usually cool down at night. So much so that in most cases you can make ice. You can use the sky as a heat sink (effectively radiating heat into space).
Thanks for the detailed information; that was genuinely informative, but I'm starting from the assumption that the required temperature swings must be present in at least some desert ecosystems as evidenced by the aforementioned documentaries. As the sibling noted, many deserts cool down quite a lot in the evenings.
Hot air can hold a lot of moisture, cold air can hold less. Water condenses on surfaces when the air cools down to the point that air would have to carry more water than it can at the new temperature.
Problem with that: it only works great in very humid areas. If you're in a desert, and have 10% humidity, you have to cool down your air by a lot for it to become too saturated and condensation to happen. Not enough cooling, and the moisture stays in the air.