English times

Noon= 12 o'clock in the afternoon

For example: "Let's meet at the station at noon." 

Midnight= 12 o'clock at night

You cannot use midnight if you are talking about 2 am, or 4 am, or any other random time during the night. It is ONLY for 12:00.
For example:"The new Harry Potter movie starts at midnight." or "I fell asleep at midnight."

So use it carefully. ^-^