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AST to CLST Converter

AST
Atlantic Standard Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CLST
Chile Summer Time
GMT -3
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

AST is 1 hour behind CLST. AST uses GMT -4, and CLST uses GMT -3 for this comparison.

For example, 8:00 am AST is 9:00 am CLST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 9am-4pm AST, which is 10am-5pm CLST.

Compare AST time with CLST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Atlantic Standard Time is 1 hour behind Chile Summer Time
8:00 am08:00 in AST is 9:00 am09:00 in CLST

AST to CLST call time
Best time for a conference call or a meeting is between 9am-4pm in AST which corresponds to 10am-5pm in CLST

8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours
9:00 am09:00 Chile Summer Time (CLST). Offset UTC -3:00 hours

8:00 am08:00 AST / 9:00 am09:00 CLST

ASTCLST
12am (midnight)1am
1am2am
2am3am
3am4am
4am5am
5am6am
6am7am
7am8am
8am9am
9am10am
10am11am
11am12pm (noon)
12pm (noon)1pm
1pm2pm
2pm3pm
3pm4pm
4pm5pm
5pm6pm
6pm7pm
7pm8pm
8pm9pm
9pm10pm
10pm11pm
11pm12am (midnight)
00:0001:00
01:0002:00
02:0003:00
03:0004:00
04:0005:00
05:0006:00
06:0007:00
07:0008:00
08:0009:00
09:0010:00
10:0011:00
11:0012:00
12:0013:00
13:0014:00
14:0015:00
15:0016:00
16:0017:00
17:0018:00
18:0019:00
19:0020:00
20:0021:00
21:0022:00
22:0023:00
23:0000:00

Atlantic Standard Time

Offset: AST is 4 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Antigua & Barbuda, Anguilla, Aruba, Barbados, St Barthelemy, Bermuda, Caribbean NL, Canada, Curaçao, Dominica, Dominican Republic, Grenada, Greenland, Guadeloupe, St Kitts & Nevis, St Lucia, St Martin (French), Martinique, Montserrat, Puerto Rico, St Maarten (Dutch), Trinidad & Tobago, St Vincent, Virgin Islands (UK), Virgin Islands (US)

Principal Cities: The largest city in the AST time zone is Santo Domingo in Dominican Republic, with about 2.202 million people. Other major cities in this time zone include Santiago de los Caballeros, Santo Domingo Oeste, San Juan, Halifax.

French: HNA - Heure Normale de l'Atlantique

Spanish: AST - Tiempo Estándar del Atlántico

AST Time Zone Geo Map
AST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Atlantic Daylight Time (ADT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Standard Time (AST) started on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Standard Time (AST) ends on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the second Sunday of March.

AST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -04 - basic short
  • -0400 - basic
  • -04:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0400 - sign character (-) followed by a four digit time providing hours (04) and minutes (00) of the offset. Indicates an offset of four hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Quebec - Military abbreviation for AST
  • Q - short form of 'Quebec'
IANA/Olson: Reflects AST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Anguilla
  • America/Antigua
  • America/Aruba
  • America/Barbados
  • America/Blanc-Sablon
  • America/Curacao
  • America/Dominica
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Grenada
  • America/Guadeloupe
  • America/Halifax
  • America/Kralendijk
  • America/Lower_Princes
  • America/Marigot
  • America/Martinique
  • America/Moncton
  • America/Montserrat
  • America/Port_of_Spain
  • America/Puerto_Rico
  • America/Santo_Domingo
  • America/St_Barthelemy
  • America/St_Kitts
  • America/St_Lucia
  • America/St_Thomas
  • America/St_Vincent
  • America/Thule
  • America/Tortola
  • America/Virgin
  • Atlantic/Bermuda
  • Canada/Atlantic
AST Abbreviation: Several time zones share AST abbreviation and it could refer to these time zones
  • Atlantic Standard Time - UTC -4
  • Arabia Standard Time - UTC +3
Time zones with the GMT -4 offset:
  • AST - Atlantic Standard Time
  • EDT - Eastern Daylight Time
  • AMT - Amazon Time
  • BOT - Bolivia Time
  • CDT - Cuba Daylight Time
  • CLT - Chile Standard Time
  • FKT - Falkland Island Time
  • GYT - Guyana Time
  • HLV - Hora Legal de Venezuela
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time

Chile Summer Time

Offset: CLST is 3 hours behind Greenwich Mean Time (GMT) and is used in South America

Countries using this time zone: Chile

Principal Cities: The largest city in the CLST time zone is Santiago in Chile, with about 4.837 million people. Other major cities in this time zone include Puente Alto, Antofagasta, Vina del Mar, Valparaiso.

CLST Time Zone Geo Map
CLST timezone map

Daylight Saving: Chile Summer Time (CLST) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Chile Standard Time (CLT).

Daylight saving time clock moves forward for one hour from 12am to 1amStart: Chile Summer Time (CLST) started on Sunday, September 7, 2025 at 12:00 am local time and clocks were set one hour forward to Sunday, September 7, 2025, 1:00 am. Daylight saving starts annually on the first Sunday of September

Daylight saving time clock moves back for one hour from 12am to 11pmEnd: Chile Summer Time (CLST) ends on Sunday, April 5, 2026 at 12:00 am local time and clocks are set one hour back to Saturday, April 4, 2026, 11:00 pm local standard time instead. Daylight saving ends annually on the first Sunday of April

CLST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -03 - basic short
  • -0300 - basic
  • -03:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0300 - sign character (-) followed by a four digit time providing hours (03) and minutes (00) of the offset. Indicates an offset of three hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Papa - Military abbreviation for CLST
  • P - short form of 'Papa'
Time zones with the GMT -3 offset:
  • ADT - Atlantic Daylight Time
  • PMT - Pierre & Miquelon Standard Time
  • PMST - Pierre & Miquelon Standard Time
  • AMST - Amazon Summer Time
  • ART - Argentina Time
  • BRT - Brasília time
  • CLST - Chile Summer Time
  • FKST - Falkland Islands Summer Time
  • GFT - French Guiana Time
  • P - Papa Time Zone
  • PYST - Paraguay Summer Time
  • SRT - Suriname Time
  • UYT - Uruguay Time
EST to ISTGMT to ESTPST to ESTEST to GMTPST to GMT