This Kestrel 3500 Weather Meter Digital Psychrometer features barometric pressure, altitude, relative humidity, heat stress index, dew point, wet bulb temperature, wind chill, air/water/snow temperature, current wind speed, average wind speed, maximum wind gust, real-time clock, large display, data hold, high precision pressure sensor, external thermistor, forecast weather with pressure trend indicator, and user-replaceable impeller.