Because clouds are reflective they can be used at night to retain heat. Farmer’s used to use smudge pots to create man-made cloud blankets that kept citrus trees from freezing. Clouds can be influenced to swing the surface temperature either direction. We can prevent an ice age or global warming with cloud control. We can’t influence the Sun, but we can influence clouds.
Smudge pots produce heat which helps to keep citrus from freezing. The smoke is pretty much gone once the pot is 'primed'. After it gets about 29 or 30 degrees F, they don't work. (former Florida Citrus Belt resident)