COT to AST Converter & Meeting Planner
Quick answer: 9:00 AM COT = 10:00 AM AST (fixed -05:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Colombia Time (COT) and Atlantic Standard Time (AST)? You need to account for the standard time difference. Atlantic Standard Time is normally 1 hours ahead of Colombia Time. Whether you are coordinating between teams in Bogotá and Medellín and Halifax and San Juan, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM COT = 1:00 AM AST. The full 24-hour COT to AST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM COT = 4:00 PM AST.
| COT Time | AST Time |
|---|---|
| 12:00 AM (00:00) | 1:00 AM (01:00) |
| 1:00 AM (01:00) | 2:00 AM (02:00) |
| 2:00 AM (02:00) | 3:00 AM (03:00) |
| 3:00 AM (03:00) | 4:00 AM (04:00) |
| 4:00 AM (04:00) | 5:00 AM (05:00) |
| 5:00 AM (05:00) | 6:00 AM (06:00) |
| 6:00 AM (06:00) | 7:00 AM (07:00) |
| 7:00 AM (07:00) | 8:00 AM (08:00) |
| 8:00 AM (08:00) | 9:00 AM (09:00) |
| 9:00 AM (09:00) | 10:00 AM (10:00) |
| 10:00 AM (10:00) | 11:00 AM (11:00) |
| 11:00 AM (11:00) | 12:00 PM (12:00) |
| 12:00 PM (12:00) | 1:00 PM (13:00) |
| 1:00 PM (13:00) | 2:00 PM (14:00) |
| 2:00 PM (14:00) | 3:00 PM (15:00) |
| 3:00 PM (15:00) | 4:00 PM (16:00) |
| 4:00 PM (16:00) | 5:00 PM (17:00) |
| 5:00 PM (17:00) | 6:00 PM (18:00) |
| 6:00 PM (18:00) | 7:00 PM (19:00) |
| 7:00 PM (19:00) | 8:00 PM (20:00) |
| 8:00 PM (20:00) | 9:00 PM (21:00) |
| 9:00 PM (21:00) | 10:00 PM (22:00) |
| 10:00 PM (22:00) | 11:00 PM (23:00) |
| 11:00 PM (23:00) | 12:00 AM (00:00)+1 day |
Best time to call Halifax from Bogotá
For most work calls, compare the normal business day in Bogotá (COT) with the business day in Halifax (AST). COT commonly covers South America, while AST is mainly associated with North America, Caribbean.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
✅ The most practical overlap on 2026-07-05 is usually 9:00 AM - 3:00 PM COT, which corresponds to 11:00 AM - 5:00 PM AST. This window sits inside the typical COT workday (9:00 AM - 6:00 PM) and the AST workday (9:00 AM - 5:00 PM).
- DST Safety: COT or AST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Colombia Stock Exchange (BVC): 09:30-16:00 local time in Bogotá.
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Frequently Asked Questions
What is the time difference between COT and AST?
During standard time, Atlantic Standard Time is 1 hours ahead of Colombia Time.
Does Colombia observe Daylight Saving Time?
Colombia does not observe Daylight Saving Time and has no current plans to do so. COT remains fixed at UTC-05:00 every day of the year, providing a consistent, unchanging reference point for international business and logistics.
How does Colombia Time (COT) align with the US?
COT (UTC-05:00) matches US Eastern Standard Time (EST) exactly during the Northern Hemisphere winter, creating zero offset between Bogotá and New York. During US Daylight Saving Time in summer, COT runs one hour behind Eastern Daylight Time (EDT, UTC-04:00), maintaining a gap narrow enough that a full shared workday remains easily achievable — one of the tightest nearshore alignments available from South America.
Does the Caribbean observe Daylight Saving Time?
The vast majority of Caribbean nations and territories — including Puerto Rico, the Dominican Republic, the US Virgin Islands, Trinidad and Tobago, and Barbados — do not observe Daylight Saving Time and remain on AST (UTC-4) year-round. This means these territories share the same clock as Halifax only during the Atlantic Standard Time window in winter, diverging by one hour once Canada and Bermuda advance to ADT each spring.
What is the difference between AST and ADT?
AST (Atlantic Standard Time) is the standard winter offset at UTC-4:00, observed from the first Sunday in November through the second Sunday in March across all AST regions. ADT (Atlantic Daylight Time) is the summer offset at UTC-3:00, applied by Eastern Canadian provinces and Bermuda when they advance their clocks by one hour during Daylight Saving Time.