Why don't the sunrise and sunset times of the watch match actual times?
A3
Sunrise and sunset time calculations are related to atmospheric refraction, which changes day by day. There is no way for calculations to take daily changes in the atmosphere into consideration. Also, calculations cannot factor in local topographic conditions, which also affect sunrise and sunset times. Finally, though calculations use longitude, latitude, and altitude data, such data provided by the GPS is not high precision, which affects calculation results.