precipitation
Fog, dew
Mac
PVC
The 4 letter word for a light rain can be mist.
mist
Mist
One word that fits this definition is mist.
ray as in a ray of light
air
pat
A three-letter word ending in "ux" is "lux," which means a unit of illumination or light.
Tan is a light brown.
day as in daylight
day
day