A light sensing system configured to determine an amount of ambient light exposure experienced by a subject, the system comprising: a primary light sensor arranged to be carried by a first device worn by the subject, the primary light sensor being configured to generate output signals conveying primary light exposure information related to an amount of ambient light to which the primary light sensor is exposed; a secondary light sensor arranged to be carried by a second device, the second device being physically separate and unconnected from the first device, and being associated with the subject, the secondary light sensor being configured to generate output signals conveying secondary light exposure information related to an amount of ambient light to which the secondary light sensor is exposed; and one or more physical computer processors configured to: if the primary light exposure information for a given time indicates that the primary light sensor is exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the primary light exposure information, and without regard to the secondary light exposure information; if the primary light exposure information for the given time indicates that the primary light sensor is not exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the secondary light exposure information, and without regard to the primary light exposure information; and if the secondary light exposure information for the given time indicates that the secondary light sensor is not exposed to ambient light, obtain tertiary light exposure information from a third light sensor that corresponds to one or more of a date, a time of day, or a geographic location in the primary and/or secondary light exposure information, the third light sensor arranged to be worn by, and/or carried by a third device associated with, another user who is not the subject, and determine the amount of ambient light exposure experienced by the subject based on the tertiary light exposure information, wherein the determined amount of ambient light exposure comprises ambient light exposure in the visible light spectrum. a primary light sensor arranged to be carried by a first device worn by the subject, the primary light sensor being configured to generate output signals conveying primary light exposure information related to an amount of ambient light to which the primary light sensor is exposed; a secondary light sensor arranged to be carried by a second device, the second device being physically separate and unconnected from the first device, and being associated with the subject, the secondary light sensor being configured to generate output signals conveying secondary light exposure information related to an amount of ambient light to which the secondary light sensor is exposed; and one or more physical computer processors configured to: if the primary light exposure information for a given time indicates that the primary light sensor is exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the primary light exposure information, and without regard to the secondary light exposure information; if the primary light exposure information for the given time indicates that the primary light sensor is not exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the secondary light exposure information, and without regard to the primary light exposure information; and if the primary light exposure information for a given time indicates that the primary light sensor is exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the primary light exposure information, and without regard to the secondary light exposure information; if the primary light exposure information for the given time indicates that the primary light sensor is not exposed to ambient light, determine the amount of ambient light exposure experienced by the subject for the given time based on the secondary light exposure information, and without regard to the primary light exposure information; and if the secondary light exposure information for the given time indicates that the secondary light sensor is not exposed to ambient light, obtain tertiary light exposure information from a third light sensor that corresponds to one or more of a date, a time of day, or a geographic location in the primary and/or secondary light exposure information, the third light sensor arranged to be worn by, and/or carried by a third device associated with, another user who is not the subject, and determine the amount of ambient light exposure experienced by the subject based on the tertiary light exposure information, wherein the determined amount of ambient light exposure comprises ambient light exposure in the visible light spectrum.