The A/FD often shows time with a "‡" symbol listed after a time range. This symbol indicates that during periods of Daylight Saving Time (DST), effective hours will be one hour earlier than what is shown in the A/FD. In those areas where DST is not observed the "‡" will not be shown.
For Example, the A/FD shows the Class D operating hours for KBZN to be 1300 to 0700Z‡. During DST observance, the operating hours are actually 1200 to 0600Z.
Image 1: KBZN A/FD listing showing the "‡" symbol after tower operating hours.
Daylight saving time is in effect from 0200 local time the second Sunday in March to 0200 local time the first Sunday in November.