Which of the following best describes the function of a METAR report?

A METAR report serves as a routine weather report specifically designed for aviation purposes. It provides current weather observations in a standardized format that pilots use to assess present conditions at an airport or aerodrome. This report typically includes information on wind direction and speed, visibility, weather phenomena, temperature, dew point, and any significant changes that may affect flying operations.

The nature of METAR reports focuses on current weather, which is critical for flight planning and safety. By providing timely and accurate information, METAR helps pilots make informed decisions regarding takeoff, landing, and navigation. It's important to note that METAR reports are updated at regular intervals, such as every hour, and may also include special reports issued when significant weather changes occur.

In contrast, the other options do not accurately represent the nature or purpose of METAR reports. Long-term weather patterns refer to climatic data rather than immediate observations. Forecasts of daily conditions are typically provided by TAF (Terminal Aerodrome Forecast) reports, which predict future weather rather than report current conditions. Historical weather data pertains to past weather conditions and is not the focus of METAR reports, which are concerned with real-time observations.