AcuRite 02049 Digital Thermometer with Indoor/Outdoor Temperature Monitor indoor and outdoor temperature (Fahrenheit and Celsius) with trend arrows that indicate whether temperature is rising or falling Wireless all-weather outdoor sensor measures temperature conditions with precision and accuracy Displays high and low records for past 12 hours, 24 hours, 36 hours, 48 hours, and for all-time Outdoor temperature sensor transmits readings every 30 seconds using a 433 MHz wireless signal up to a 165 foot (50 meter) range Display and outdoor sensor are totally wireless and easy to install