MaxiMet GMX531 Compact Weather Station with GPS and Heating. 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 ...