The phrases "at night" and "in the night" are both used to talk about events that happen during nighttime, but they have slightly different meanings and uses.
“At Night” – General Time Reference
We use "at night" to refer to things that happen regularly or generally during the nighttime hours (usually after sunset and before sunrise).
• I usually read a book at night.
• Bats fly at night.
• She works at night and sleeps during the day.
“In the Night” – Specific Moment or Event
"In the night" is used to describe something that happens once, or at a particular moment during the night—often unexpectedly or memorably.
• I heard a strange noise in the night.
• He woke up screaming in the night.
• A storm passed through in the night.
Quick Summary
- At night = habitual or general reference to nighttime.
- In the night = specific event during one particular night.
While native speakers may sometimes use them interchangeably in casual speech, understanding this distinction helps you speak and write more precisely in English.