The most common and most likely answer to this crossword clue is the 3 plus 3 letter word ALL DAY
I've seen this crossword clue in Independent
A
L
L
D
A
Y
More clues leading to the result ALL DAY
Buddy explains!

The straight part
We know that "dawn to dusk?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dawn to dusk? = all day.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ALL DAY mean?
ALL DAY adjective- Lasting throughout the whole day.
- Available throughout the whole day.