What does the acronym METAR stand for?

The acronym METAR stands for Aviation Routine Weather Report. This is a standardized format used by meteorological authorities around the world to communicate weather information to pilots and air traffic control. A METAR report includes essential data such as temperature, dew point, wind direction and speed, visibility, cloud cover, and any significant weather phenomena, which helps pilots in their pre-flight planning and during flight.

The format and frequency of these reports—typically issued at least once an hour—ensure that weather information is current and relevant for aviation operations. This is critical for flight safety, as it allows pilots to assess conditions along the route and at the destination, aiding in decision-making regarding takeoffs, landings, and alternative planning.

The other options described in the question do not accurately reflect the content or purpose of METAR reports, as they misrepresent the report's focus on routine aviation weather, rather than environmental assessments or temperature measurements in various non-aviation contexts.