A sensor package can have a reference thermopile sensor and a reference temperature sensor disposed therein to determine an ambient temperature. In one or more implementations, the sensor package includes a substrate having a substrate surface, a reference thermopile sensor disposed over the substrate surface, a reference temperature sensor disposed over the substrate surface, and a lid assembly disposed over the thermopile sensor and the reference thermopile sensor. The lid assembly includes a structure having a transparent portion that passes electromagnetic radiation occurring in a limited spectrum of wavelengths. The reference thermopile sensor generates a reference thermopile sensor signal representing a difference between a temperature of the substrate surface and a temperature of a lid assembly surface. An external ambient temperature can be determined based upon the reference thermopile sensor signal.