Although snow is cold, a covering of snow protects the plants under it from freezing when the temperature of the air is colder than snow.
(snow; is; cold) (a covering of snow; protects; the plants under it; from freezing) (the temperature of the air; is; colder than snow)
snow a covering of snow the temperature of the air
is protects is
cold
the plants under it from freezing
colder than snow