Looking on the internet deeply has found these results:

until late at night is the most popular phrase on the web.

until late in the night 1914,000 results on the web	until late at night 11,230,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
He'd type until late into the night, then put what he'd typed in a drawer. Each taught the other his language and his culture until late at night. We worked until dawn, and then we would shoot until late at night in the studio. It'll take me until late into the night. It'll take me until late into the night. Until late one night, I came home to find Mike. Defense was unaware of their identity until late last night. We didn't find out about you until late last night.	He often used to stay up until late at night. She stays out every day until late at night. He made me work from 4:00 in the morning until late at night. To raise four of us, my parents have to work from early morning until late at night raking mussels along the river to sell in the market. He practices playing the guitar until late at night. Farmhands work from dawn until late at night evey day. We worked until dawn, and then we would shoot until late at night in the studio. Like Balzac, the Commission drinks coffee from the morning until late at night, in order to be able to fulfil its duties.

until late in the night

1914,000 results on the web

until late at night

11,230,000 results on the web

More popular!

He'd type until late into the night, then put what he'd typed in a drawer.
Each taught the other his language and his culture until late at night.
We worked until dawn, and then we would shoot until late at night in the studio.
It'll take me until late into the night.
It'll take me until late into the night.
Until late one night, I came home to find Mike.
Defense was unaware of their identity until late last night.
We didn't find out about you until late last night.

He often used to stay up until late at night.
She stays out every day until late at night.
He made me work from 4:00 in the morning until late at night.
To raise four of us, my parents have to work from early morning until late at night raking mussels along the river to sell in the market.
He practices playing the guitar until late at night.
Farmhands work from dawn until late at night evey day.
We worked until dawn, and then we would shoot until late at night in the studio.
Like Balzac, the Commission drinks coffee from the morning until late at night, in order to be able to fulfil its duties.