definite article in [from the early morning to the late...]

[ansonman]

I have made up the sentences below

(1a) Next Monday, John will stay here from early morning until late afternoon.

(1b) Next Monday, John will stay here from the early morning until the late afternoon.

Most of my non-native friends think (1a) without the definite article sounds better. I don't know why (1b) is wrong.

Please explain this. Thank you.

[Alan]

(b) is not wrong but (a) is more natural.