Plan your day with confidence. The high-precision 5-in-1 weather sensor accurately measures five different conditions, including rainfall, wind speed and wind direction, outdoor temperature and humidity, giving you comprehensive data about the elements surrounding your home. Unlike regional weather predictions from sources like the news or online, AcuRite weather forecast products rely on sensors that collect organic data right from your backyard. AcuRite's 5-in-1 sensor-based weather station tracks specific sets of weather related variables, including changes in temperature, humidity, and barometric pressure to generate a forecast with pinpoint accuracy personalized for your location. It combines the latest methodology in weather prediction modeling with the related effects of current localized weather observations to provide a reliable, accurate forecast. Its patented self-calibrating weather forecasters use a unique algorithm to analyze changes in pressure and temperature over 14 days (called 14-day learning mode) to determine your altitude. Measuring changes in barometric pressure adjusted for your location's altitude is a proven method for determining the future weather forecast. Self-Calibrating Forecasting Technology makes AcuRite weather stations simple to install and extremely accurate. The sensor itself is wireless, simple to install and works down to -40 degrees. The colour display unit measures 8.2" H x 7.4" W x 1.2" D and the outdoor sensor measures 10.8" H x 5.6" W x 13.8" D. The outdoor sensor uses 4 x AA alkaline or lithium batteries (not included) - Lithium batteries are recommended for temperatures below -4ºF/-20ºC. The colour display unit uses a 5V AC power adapter included and recommended for optimal display color (or 3 x AA alkaline batteries not included).