I should perhaps have pointed to the difference between a dry and a humid night. I've never experienced the world's hot deserts myself, but I've read that nights actually get cold in the dry air, as there is no water vapour to retain heat. Whereas August in central Italy - which I experienced for several years - gives you nighttime minima in the mid to high twenties due to high humidity retaining the heat. It's why Romans traditionally get out in August, either into the mountains or south to Sicily, where the fierce heat of day is balanced by cooler nights due to lower humidity.
it's more complex still, on clear nights heat from the ground escapes into the upper atmosphere then space , cloudy nights all other things being equal will be warmer than clear nights, however water conducts heat so wet clothes transfer body heat faster than dry clothes, one feels warmer in a dry cold wearing insulated clothing at -20c than at warmer but more humid temperatures either side of 0c. Water in the form of snow reflects heat back into space whereas dark coloured forests and land surfaces absorb heat. So the humidity in our clothing in winter makes us feel colder as it conducts heat away from the body, but humidity in summer makes us feel hotter because the system of sweat evaporation does not work so well at losing heat.