Possible Clues:

• Start of the week
• After the sun goes down this comes up
• Day whose child is fair of face
• Start of working week
• Work week start
• After sundown this comes for a whole day
• With 26-Across, #1 hit for the Mamas & the Papas
• Workweek start, or an apt title for this puzzle based on an abbreviation found in its five longest answers
• When the sun goes down this comes up
• See 23 and 24