Methods, systems, computer-readable media, and apparatuses for determining indoor/outdoor state of a mobile device are presented. In some embodiments, a sensor reading is obtained from a sensor accessible by the mobile device. Contemporaneous information related to a local condition associated with an area where the mobile device is located is obtained. At least the sensor reading and the information related to a local condition are provided as input to an indoor/outdoor detection model selected from a plurality of trained models. Based on the model, the mobile device is classified as indoors or outdoors.