CAT to AST Converter & Meeting Planner
Quick answer: 9:00 AM CAT = 3:00 AM AST (fixed +02:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Central Africa Time (CAT) and Atlantic Standard Time (AST)? You need to account for the standard time difference. Atlantic Standard Time is normally 6 hours behind Central Africa Time. Whether you are coordinating between teams in Johannesburg and Harare 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 CAT = 6:00 PM AST. The full 24-hour CAT to AST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM CAT = 9:00 AM AST.
| CAT Time | AST Time |
|---|---|
| 12:00 AM (00:00) | 6:00 PM (18:00)-1 day |
| 1:00 AM (01:00) | 7:00 PM (19:00)-1 day |
| 2:00 AM (02:00) | 8:00 PM (20:00)-1 day |
| 3:00 AM (03:00) | 9:00 PM (21:00)-1 day |
| 4:00 AM (04:00) | 10:00 PM (22:00)-1 day |
| 5:00 AM (05:00) | 11:00 PM (23:00)-1 day |
| 6:00 AM (06:00) | 12:00 AM (00:00) |
| 7:00 AM (07:00) | 1:00 AM (01:00) |
| 8:00 AM (08:00) | 2:00 AM (02:00) |
| 9:00 AM (09:00) | 3:00 AM (03:00) |
| 10:00 AM (10:00) | 4:00 AM (04:00) |
| 11:00 AM (11:00) | 5:00 AM (05:00) |
| 12:00 PM (12:00) | 6:00 AM (06:00) |
| 1:00 PM (13:00) | 7:00 AM (07:00) |
| 2:00 PM (14:00) | 8:00 AM (08:00) |
| 3:00 PM (15:00) | 9:00 AM (09:00) |
| 4:00 PM (16:00) | 10:00 AM (10:00) |
| 5:00 PM (17:00) | 11:00 AM (11:00) |
| 6:00 PM (18:00) | 12:00 PM (12:00) |
| 7:00 PM (19:00) | 1:00 PM (13:00) |
| 8:00 PM (20:00) | 2:00 PM (14:00) |
| 9:00 PM (21:00) | 3:00 PM (15:00) |
| 10:00 PM (22:00) | 4:00 PM (16:00) |
| 11:00 PM (23:00) | 5:00 PM (17:00) |
Best time to call Halifax from Johannesburg
For most work calls, compare the normal business day in Johannesburg (CAT) with the business day in Halifax (AST). CAT commonly covers Southern Africa, Central Africa, 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 2:00 PM - 5:00 PM CAT, which corresponds to 9:00 AM - 12:00 PM AST. This window sits inside the typical CAT workday (8:00 AM - 5:00 PM) and the AST workday (9:00 AM - 5:00 PM).
- DST Safety: CAT or AST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Johannesburg Stock Exchange (JSE): 09:00-17:00 local time in Johannesburg.
🔥 Popular CAT & AST Converters
Frequently searched time zone conversions related to your search.
Related Time Converters
Explore nearby time zone offsets and reverse conversions related to CAT and AST.
Frequently Asked Questions
What is the time difference between CAT and AST?
During standard time, Atlantic Standard Time is 6 hours behind Central Africa Time.
Does the Central Africa Time zone observe Daylight Saving Time?
None of the countries observing Central Africa Time use Daylight Saving Time. South Africa abolished DST in 1994, and no other CAT-observing nation currently applies seasonal clock changes — CAT remains permanently fixed at UTC+02:00 throughout the year.
Which major countries use Central Africa Time (CAT)?
Central Africa Time is observed by South Africa, Zimbabwe, Zambia, Botswana, Mozambique, Malawi, and Eswatini. South Africa is the zone's dominant economy, with Johannesburg functioning as the region's primary financial center and home to the Johannesburg Stock Exchange (JSE), Africa's largest equity market by capitalization.
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.