When the air temperature at the ground is less than 32 F, the precipitation begins falling as snow from the clouds.
(the air temperature at the ground; is; less than 32 F) (the precipitation; begins; T:When the air temperature at the ground is less than 32 F) (the precipitation; falling; as snow; from the clouds)
the air temperature at the ground the precipitation the precipitation
is begins falling
less than 32 F
T:When the air temperature at the ground is less than 32 F
as snow from the clouds