During summer when daylight saving time is observed, your time is 12 hours ahead of EDT. So, 12pm 7/18 EDT would be your 0:00am 7/19. In winter, you are 13 hours ahead so 12pm 12/24 EST (Eastern Standard Time) would be your 1am 12/25.
During summer when daylight saving time is observed, your time is 12 hours ahead of EDT. So, 12pm 7/18 EDT would be your 0:00am 7/19. In winter, you are 13 hours ahead so 12pm 12/24 EST (Eastern Standard Time) would be your 1am 12/25.