English lesson at • on • in

Meet me in at three o'clock in front of the library.

My interview will be held on Friday morning. ('on' is correct but it isn't necessary when speaking)

We're flying to Italy in July.

Craig was supposed to be here at noon, but he's late again.

My birthday is in June. When's yours?

In the fall, the forest is breathtaking!

At In North America, Christmas is celebrated on December 25th.

Will you be working on Saturday? ('on' is correct but not necessary when speaking)

The concert starts at 7 pm. Don't be late!