dew

waterdrops that form

on the ground at night

 when humid air cools

frost

ice crystals that form

on the ground

at night

when humid air cools

to below freezing 

hail

balls of ice that fall

during a thundestorm

precipitation

forms of water

that come out of the air

sleet

rain that freezes

 as it falls

if the clouds are freezing cold,

the water comes out as

snow

both dew and frost

are precipitation

that happens at

night

to have dew

or

frost

the air must be humid

and the ground must be cold