A ceilometer uses a light source or a laser to measure the cloud base's height. To gather the information used to measure the cloud base height the ceilometer reflects a light beam or laser off the cloud base from the ground and uses either travel time or triangulation to calculate the distance.

Laser ceilometers in meteorology are used for a variety of purposes including measuring aerosol in the atmosphere, cloud formations, the structure of the atmosphere, the composition of the atmosphere, precipitation, gas presence, gas concentration, wind turbulence, wind speed, changes in wind conditions, and to detect wind currents.