There are no official rules, but in American English the day is usually split like this: morning from about 5 AM to 12 PM, afternoon from 12 PM to about 5 PM, evening from about 5 PM to 9 PM, and night from about 9 PM until early morning. Noon is the only fixed line: morning always ends at 12 PM.
Parts of the day chart
| Part of day | Typical hours | 24-hour clock | Greeting |
|---|---|---|---|
| Early morning | 5:00 AM – 8:00 AM | 05:00 – 08:00 | Good morning |
| Morning | 8:00 AM – 12:00 PM | 08:00 – 12:00 | Good morning |
| Noon / midday | 12:00 PM | 12:00 | Good afternoon (from noon) |
| Afternoon | 12:00 PM – 5:00 PM | 12:00 – 17:00 | Good afternoon |
| Evening | 5:00 PM – 9:00 PM | 17:00 – 21:00 | Good evening |
| Night | 9:00 PM – 4:00 AM | 21:00 – 04:00 | Good evening / good night (when leaving) |
| Midnight | 12:00 AM | 00:00 | — |
Why the boundaries are fuzzy
Only the morning–afternoon boundary is fixed by the clock, because "afternoon" literally means "after noon" and AM/PM switches at 12. See AM and PM explained. The other boundaries depend on:
- Daylight and season: at 5:30 PM in December it's dark and feels like evening; at 5:30 PM in June it's bright and still feels like afternoon.
- Routine: for many people evening begins when the workday ends, and night begins when they head to bed.
- Region and language: in Spain or Argentina, where dinner is often at 9 or 10 PM, "afternoon" (tarde) can stretch to 8 or 9 PM.
Is 12:30 AM night or morning?
Technically 12:30 AM is in the morning of the new day, but most people call the hours after midnight "late at night" until they go to sleep. If you're up at 2 AM after a party, it's "last night"; if you're up at 4:30 AM for a flight, it's "early morning". When it matters, such as for deliveries, appointments or medication, give the date and time instead of a word like "tonight".
What do "tonight", "midnight" and "end of day" mean?
- Tonight means the evening and night of the current date, usually from around 6 PM until you go to sleep.
- Midnight is 12:00 AM, the first moment of the next date. "Midnight on Friday" is ambiguous, so say "11:59 PM Friday" or "the night between Friday and Saturday".
- End of day (EOD) in business usually means close of business, around 5 PM in the sender's time zone, though some people mean 11:59 PM. Ask if a deadline depends on it.
- Close of business (COB) is generally 5 PM local time.
- Midday is noon, but people often use it loosely for roughly 11 AM to 2 PM.
Dawn, dusk and twilight
Astronomers define the edges of the day more precisely, using the Sun's position:
- Dawn begins when the sky starts to lighten before sunrise.
- Sunrise is when the top of the Sun appears on the horizon.
- Sunset is when the Sun disappears below the horizon.
- Civil twilight continues until the Sun is 6° below the horizon, about 20–40 minutes after sunset in most of the US. After that, artificial light is usually needed outdoors.
- Dusk is the darkest stage of twilight, just before full night.
Sunrise and sunset times shift through the year as the seasons change; the longest and shortest days are covered in our guide to the solstices.
Greetings etiquette
- "Good morning" until noon, "good afternoon" until about 5 or 6 PM, and "good evening" after that.
- "Good night" is a farewell, not a greeting. You say it when leaving or going to bed, never when arriving.
- For emails read across time zones, a neutral "Hello" or "Hi" avoids wishing someone a good morning at their midnight.
What part of the day is it for them? Before you call someone abroad, check their local time with the time zone converter.
Frequently asked questions
What time is afternoon?
From 12:00 PM (noon) to about 5:00 PM.
What time does evening start?
Usually around 5 or 6 PM, often when the workday ends or the sun starts to set.
Is 6 PM evening or night?
Evening. Night typically begins around 9 PM.
When does morning start?
Many people count morning from about 5 or 6 AM, around sunrise, but technically any time after midnight is AM.