Determining time spent outdoors. A method includes, at a first time, using one or more primary criteria including one or more criteria related to information provided by a first hardware input sensor on a device, to determine that the device is outdoors. The method further includes at one or more other times, using one or more secondary criteria, different than the primary criteria, the secondary criteria related to information provided by one or more second hardware input sensors, to determine continuity of the device being outdoors from the first time to the one or more other times. The method further includes based on determining that the device is outdoors and determining continuity of the device being outdoors from the first time to the one or more other times, identifying a total amount of time that the device has been outdoors.
