corrections to above

No GPS is involved. It receives signal (very low frequency) from Fort Collins, CO. Said signal includes day, date, time and daylight savings info. You DO have to program it for the correct time zone. It automatically sync's itself at night (when the radio signal is strongest - less atmospheric interference at night). It will try to sync 4 times each night. Ability to sync depends greatly on location of the watch. Nearby large buildings can mess it up, weather can mess it up, etc. That's why it tries to sync 4 times each night.