Humidity
Videos
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.
Paranal Observatory on Cerro Paranal in the Atacama Desert is one of the driest places on Earth.
A hygrothermograph for humidity and temperature recording
Hygrometer for domestic use, wet/dry psychrometer type
Thermo hygrometer displaying temperature and relative humidity
Fog
Videos
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare.
Light fog in Bangladesh
Minute droplets of water constitute this after-dark radiation fog, with an ambient temperature of −2 °C (28 °F). Their motion trails are captured as streaks.
A close-up view of water droplets forming fog. Those outside the camera lens's depth of field appear as orbs.
Advection fog layer in San Francisco with the Golden Gate Bridge and skyline in the background