CLT to AST
+0hCLT
CLTSOURCEAST
ASTGreen rows indicate typical business hours (9 AM - 5 PM)
CLT and AST on the World Map
The map below highlights the CLT (Chile Standard Time) and AST (Atlantic Standard Time) timezone regions across the globe.
CLT – Chile Standard Time
UTC-04:00Chile Standard Time (CLT) is the time zone for continental Chile, 4 hours behind UTC.
- •Chile observes daylight saving time, switching to CLST (UTC-03:00) in summer.
- •Santiago is the largest city in Chile with over 6 million in the metro area.
- •Chile spans over 4,300 km from north to south but uses one timezone.
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
Comparing Time Zones: CLT and AST
CLT runs on Chile Standard Time (CLT) at UTC-04:00. AST runs on Atlantic Standard Time (AST) at UTC-04:00. That puts CLT no time difference AST — a difference of +0h at the current offsets.
In practice, when it is 9:00 AM in CLT it is 9:00 AM in AST. Midnight in CLT is 12:00 AM in AST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
CLT to AST time conversion table
| CLT (CLT) | AST (AST) | Day |
|---|---|---|
| 12:00 AM | 12:00 AM | same day |
| 6:00 AM | 6:00 AM | same day |
| 7:00 AM | 7:00 AM | same day |
| 8:00 AM | 8:00 AM | same day |
| 9:00 AM | 9:00 AM | same day |
| 12:00 PM | 12:00 PM | same day |
| 3:00 PM | 3:00 PM | same day |
| 5:00 PM | 5:00 PM | same day |
| 6:00 PM | 6:00 PM | same day |
| 9:00 PM | 9:00 PM | same day |
Why people convert CLT to AST time
- Scheduling a call from CLT to AST: a 10:00 AM start in CLT lands at 10:00 AM in AST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both CLT and AST are inside the 9-to-5 working day between 9:00 AM and 5:00 PM CLT time (9:00 AM–5:00 PM AST). That is roughly 8 hours of usable overlap.
- Watching a live event or market open: CLT viewers need 9:00 AM in AST to catch a 9:00 AM start there, and 12:00 AM if the event is anchored to CLT.
- Always state the zone abbreviation, not just the hour. "3:00 PM CLT" is unambiguous; "3 PM" across a +0h gap is not.
- Block 9:00 AM–5:00 PM CLT as the recurring meeting window if you work primarily from CLT and need AST colleagues present.
About CLT (Chile Standard Time)
Chile Standard Time (CLT) is the standard time in Chile. During summer months (October to March), Chile switches to Chile Summer Time (CLST, UTC-03:00). Chile is the longest north-south country in the world.
About AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
Best time to call between CLT and AST
Both CLT and AST sit inside the 9 AM – 5 PM working day between 9:00 AM–5:00 PM CLT, which is 9:00 AM–5:00 PM AST. That gives roughly 8 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
CLT and AST share 8 hours of working-hours overlap (9:00 AM–5:00 PM CLT), so scheduling a live meeting is straightforward.
CLT is no time difference AST (CLT UTC-04:00 → AST UTC-04:00). The shared working window is 9:00 AM–5:00 PM CLT. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
CLT
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Apr 4, 2027
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between CLT and AST?
CLT (CLT, UTC-04:00) is no time difference AST (AST, UTC-04:00). The gap is currently +0h.
How do I convert CLT time to AST time?
Add +0h to CLT local time. For example, 9:00 AM in CLT is 9:00 AM in AST.
What time is it in AST right now?
AST uses AST at UTC-04:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +0h offset from CLT.
What is the best time to call AST from CLT?
Call between 9:00 AM and 5:00 PM CLT — that maps to 9:00 AM–5:00 PM AST and keeps both parties inside the working day.
Which is ahead, CLT or AST?
CLT and AST are currently on the same clock.
Does daylight saving time affect the CLT–AST difference?
Neither zone observes daylight saving time, so the +0h offset between CLT and AST is fixed all year.
Which other cities share CLT's time zone?
CLT also covers Santiago, Valparaíso, Concepción, Viña del Mar, Antofagasta.
Which countries use CLT, CLT's zone?
CLT is used in Chile.
What is the time difference between CLT and AST?
AST is +0h from CLT.
What timezone is CLT in?
CLT operates on its local timezone.
What timezone is AST in?
AST operates on its local timezone.
Which countries use CLT (Chile Standard Time)?
CLT is used in Chile.
Does CLT observe daylight saving time?
Yes, CLT switches to CLST during summer months.
What are some interesting facts about CLT?
Chile observes daylight saving time, switching to CLST (UTC-03:00) in summer. Santiago is the largest city in Chile with over 6 million in the metro area.
Which cities are in the AST timezone?
Major cities in the AST timezone include Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
What is the UTC offset for AST?
Atlantic Standard Time (AST) is at UTC-04:00. During daylight saving time, it shifts to ADT.
What should I know about the AST timezone?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
When is it midnight in CLT, what time is it in AST?
When it is 12:00 AM (midnight) in CLT (CLT), it is +0h later in AST (AST).
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See every conversion from CLT →·See every conversion from AST →