MaxiMet GMX531 Compact Weather Station with GPS. Measured Parameters: Relative Wind Speed, Wind Direction, Air Temperature, Relative Humidity, Barometric Pressure, Solar Irradiance, Rainfall, 2-Axis Compass Heading, GPS Location, Heading and Speed. Derived Parameters: Average Wind Speed & Direction, Corrected Direction, Gust Speed & Direction, True Wind Speed and Direction correcting for misalignment or motion, Height above Sea Level, Dew Point, Wet Bulb Temperature, Wind Chill, Heat Index, Absolute Humidity, Air Density, Pressure at Sea Level, ...