The Active Air Indoor-Outdoor Thermometer can be used indoors or outdoors to help achieve and monitor desired growing conditions for your plants. It features a large display and a remote probe that takes two temperatures at the same time. This unique feature allows for you to monitor and record high and low points for temperature and humidity. It delivers readings in either °F or °C. Experiment to determine the best results for your plants. On average, most species prefer temperatures around ≈80 °F, with humidity levels of ≈50%.