Note that the sensor points upward and thus does not measure solar radiation reflected upward from the ground. Radiation at high sun angles near 70 degrees seem to induce the worst errors. For design reasons, this sensor is mounted within the same membrane shell as the relative humidity sensor. As a result, the response time of the TAIR is somewhat longer than would be the case for free air exposure. This thermistor has the same warm bias on calm, high-radiation days as does the 1.5 meter thermistor.
Wind chill represents the cooling effect on the human body of low temperatures combined with wind.
When WSPD is zero, WDIR and other 10-meter wind parameters are set to zero. The standard deviation of the wind direction at 10 meters. This parameter is a measure of the steadiness of wind direction. The standard deviation may be large for either inclement weather or relatively light winds. Same as average wind speed for 10 meters except the anemometer is positioned at 2 meters.