Possible Clues:

• Dawn gets just twenty-four hours off?
• Time of awakening
• Twenty-four-hour baker's round at first light
• Daughter's always getting time off, it dawns on us
• Vampire's curfew
• Dawn away from desk after period of time
• Cockcrow
• First light ... or a phenomenon suggested by this puzzle's seven sets of circled letters?
• When the cock crows
• Wake-up time, for some