This document defines key weather-related terms and concepts: - It describes weather as the condition of the atmosphere in a certain area at a given time. It also discusses meteorology, meteorologists, and the Philippine Atmospheric Geophysical Astronomical Services Administration. - Key weather elements that are described include air temperature, wind speed and direction, cloud formation, and rainfall. Instruments for measuring these such as thermometers, anemometers, wind vanes, rain gauges, and barometers are also outlined. - The Beaufort scale for describing wind speed is mentioned, as are terms for describing cloud coverage such as clear, partly cloudy, and overcast.