Twilight - Before sunrise and again after sunset there are intervals of time during which there is enough natural light provided by the upper atmosphere, which does receive direct sunlight and reflects part of it toward the Earth's surface. Some outdoor activities may be conducted without artificial illumination during these intervals of twilight. It is useful to have some means to set limits beyond which a certain activity should be assisted by artificial lighting.

isodrosotherm - A line of equal dew point temperature. Isodrosotherms are typically drawn for surface dew points. They can give meteorologists a good read on where surface fronts are located since tightly packed isodrosotherms indicate a dew point gradient.

Squall Line - A line of intense thunderstorms that are accompanied by high winds and heavy rain. Squall lines typically move through quickly and oftentimes occur along or ahead of a fast moving cold front. These lines can sometimes extend for hundreds of miles.

Chionophobia - A person who suffers from Chionophobia has an irrational fear of snow or snow storms.

La Nina - La Nina is the cool phase of the El Nino-Southern Oscillation cycle. During a La Nina event, the east-central Equatorial Pacific Ocean becomes abnormally cool due to stronger than normal trade winds. La Nina events are a boon to the Peruvian fishing industry due to the nutrient rich waters that develop off the coast of western South America. Global weather patterns can also be influenced by the presence of a La Nina.

Turbulence - Any irregular or disturbed flow in the atmosphere caused by eddies and vertical air currents. Regions of the atmosphere that are characterized by turbulence will often be found in the vicinity of frontal boundaries. Thunderstorms produce the most severe turbulence due to the intense upward and downward vertical air currents that occur in the vicinity of them.

Green flash - A brilliant green color that can appear on the upper limb of the sun as it rises or sets. It is believed that it occurs due to atmospheric refraction and is most commonly seen at sunset. On rare occasions it has been seen as a green ray of light briefly shooting up from the sun as it rises or sets.