day time (daytime)

Quick answer: write daytime as one word when you mean the hours of natural light or an adjective describing those hours. Use during the day or in the daytime when a phrase sounds better.

Quick answer

Use daytime (one word) for the period of daylight and as an adjective (daytime activities). Avoid day time and day-time in standard writing; use during the day or in the daytime when you need a phrase.

daytime - standard one-word form (noun or adjective): daytime traffic, daytime schedule.
during the day / in the daytime - natural alternatives for smoother phrasing.
day time / day-time - usually incorrect or stylistically odd; only follow a specific house style.

Core explanation (spacing, hyphenation, grammar)

Dictionaries and most style guides treat daytime as a solid compound. When the idea is a single concept - the hours of daylight - English fuses the words.

Spacing (day time) is usually an error. Hyphenation (day-time) looks dated and is almost never needed. Treat daytime like similar compounds: nighttime, lunchtime, daylight.

Function rule: If the term modifies a noun, use the compound: daytime rates, daytime shift.
Phrase rule: If you naturally use a preposition, prefer during the day or in the daytime for rhythm: We met during the day.

Real usage: work, school, casual (copyable lines)

Use these ready-to-copy sentences in emails, memos, syllabi, or casual messages.

Work:
Wrong: The day time support team will respond within 24 hours. →
Right: The daytime support team will respond within 24 hours.
Work:
Wrong: Please schedule the demo in the day time window. →
Right: Please schedule the demo during the daytime window.
Work (alternate): Our daytime team is available from 9-17; the night team covers 17-01.
School:
Wrong: Day time classes meet Monday-Friday. →
Right: Daytime classes meet Monday-Friday.
School:
Wrong: Turn in the homework in the day time. →
Right: Turn in the homework during the daytime.
School (alternate): Daytime seminars are held in Room 210; evening seminars are online.
Casual:
Wrong: I nap in the day time sometimes. →
Right: I nap during the daytime sometimes.
Casual:
Wrong: They only play outside at day time. →
Right: They only play outside during the day.
Casual (alternate): I prefer daytime hikes because they're less buggy.

Examples: realistic wrong/right pairs (copy these fixes)

Common slips and their corrected forms - copy the right-hand sentence into your draft.

Work:
Wrong: We should schedule the call in the day time tomorrow. →
Right: We should schedule the call during the daytime tomorrow.
Work:
Wrong: The day time shift starts at 8 a.m. →
Right: The daytime shift starts at 8 a.m.
Work:
Wrong: Send reports during day time hours. →
Right: Send reports during daytime hours.
School:
Wrong: Day time lectures are in Hall A. →
Right: Daytime lectures are in Hall A.
School:
Wrong: Please submit the form in day time Friday. →
Right: Please submit the form during the daytime on Friday.
School:
Wrong: We have day time labs and evening tutorials. →
Right: We have daytime labs and evening tutorials.
Casual:
Wrong: I exercise in the day time when I'm free. →
Right: I exercise during the day when I'm free.
Casual:
Wrong: They only visit at day time. →
Right: They only visit during the daytime.
Casual:
Wrong: It's day-time out there - bring sunglasses. →
Right: It's daytime out there - bring sunglasses.
General: Wrong: Day time temperatures were unusually high. →
Right: Daytime temperatures were unusually high.
General: Wrong: Is it day-time or night-time? →
Right: Is it daytime or nighttime?
General: Wrong: The best time to call is day time. →
Right: The best time to call is during the daytime.

How to fix your sentence (practical checklist + rewrites)

Quick method for any instance of day time / day-time / daytime.

Step 1: Identify the function - does it modify a noun (adjective) or sit in a phrase? If it modifies a noun → daytime.
Step 2: If it reads clunky, rewrite to during the day, in the daytime, or choose a specific time (morning, afternoon).
Step 3: Read aloud; if the rhythm feels forced, pick the phrase or a specific time.

Rewrite:
Original: "We met in the day time, not at night." → Fix: "We met during the daytime, not at night." → Alternate: "We met in the afternoon, not at night."
Rewrite:
Original: "Day time activities are canceled." → Fix: "Daytime activities are canceled." → Alternate: "Activities scheduled for the day are canceled."
Rewrite:
Original: "The best time to call is day time." → Fix: "The best time to call is during the daytime." → Shorter: "Call in the afternoon."
Pattern: [adjective use] → daytime + noun (daytime parking rules). [phrase use] → during the day + verb (We clean the lab during the day).

Try your own sentence

Test the whole sentence rather than the isolated phrase - context makes the right form clearer.

Memory trick: a fast way to avoid the error

Single idea = single word. If "day + time" names one combined idea (hours of daylight), glue them: daytime.

Think "one-word sunlight" - daytime equals one concept, one word.
If you use a preposition naturally (during, in), keep the phrase separate: during the day.
Example: daytime traffic (one concept) vs. drive during the day (phrase with preposition).

Similar mistakes to watch for (quick corrections)

Apply the same check to other fused or split forms you see often.

nighttime - not night time
daylight - not day light
a lot - two words (not alot)
all day - two words as an adverbial phrase (not allday)

Wrong: I left my keys out in the day light. →
Right: I left my keys out in the daylight.
Wrong: I have alot of homework due. →
Right: I have a lot of homework due.
Wrong: We worked night time hours. →
Right: We worked nighttime hours.

Final tips and quick editing steps

When editing, search for day time and day-time and apply the checklist: replace with daytime when it modifies a noun; use during the day or a specific time when a phrase reads better.

Search and replace "day time" and decide per instance: daytime or during the day.
Keep a brief personal style note for frequent entries (daytime, a lot, preferred spellings).
Use a grammar tool to flag nonstandard spellings and suggest rewrites.
Tip: For headlines, daytime is concise: "Daytime Traffic Delays Expected."

Want a quick check (soft CTA)

Need a second opinion? Paste a sentence into a grammar checker or ask a colleague: "Is 'day time' correct here?" A tool will flag spacing issues and suggest daytime or phrasing alternatives so you can choose the best tone and rhythm.

FAQ

Is 'day time' ever correct?

In contemporary standard English, no - daytime is the correct one-word form. If you need a two-word phrase for rhythm, use during the day or in the daytime rather than day time.

Should I ever use 'day-time' with a hyphen?

Hyphenating day-time is not standard and reads dated. Only use it if a specific house style demands it; otherwise prefer daytime or a phrase.

How can I quickly fix 'day time' across a long document?

Search for "day time" and handle each instance: if it modifies a noun, replace with daytime; if it sits in a phrase, rewrite to during the day or pick a specific time like afternoon.

When should I use 'daytime' versus 'afternoon'?

Afternoon names a specific part of the day after noon. Use afternoon for precision; use daytime for broader daylight hours or to contrast day and night.

Do major style guides prefer 'daytime'?

Yes. Major dictionaries and style guides list daytime as one word. Use the single-word form unless an editor's house style specifies otherwise.

Check the whole sentence before you send it

Always read the full sentence aloud. Context and rhythm usually point to the best form: daytime, during the day, or a specific time like morning or afternoon.