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PDT to AST

+3h

PDT

PDTSOURCE
UTC-07:00☀ DST active
HH12
:
MM00
  
12:00 (24-hr)
12 AM6 AM12 PM6 PM12 AM

AST

AST
UTC-03:00☀ DST active
HH03
:
MM00
  
15:00 (24-hr)
12 AM6 AM12 PM6 PM12 AM
PDT
AST
12:00 AM
4:00 AM
2:00 AM
6:00 AM
4:00 AM
8:00 AM
6:00 AM
10:00 AM
8:00 AM
12:00 PM
10:00 AM
2:00 PM
12:00 PM
4:00 PM
2:00 PM
6:00 PM
4:00 PM
8:00 PM
6:00 PM
10:00 PM
8:00 PM
12:00 AM+1
10:00 PM
2:00 AM+1

Green rows indicate typical business hours (9 AM - 5 PM)

PDT and AST on the World Map

The map below highlights the PDT (Pacific Daylight Time) and AST (Atlantic Standard Time) timezone regions across the globe.

PDTASTLos AngelesSan FranciscoSeattleVancouverHalifaxSan JuanSanto DomingoCaracas
PDT Zone
→
AST Zone

Explore all world timezones interactively →

PDT – Pacific Daylight Time

UTC-07:00

Pacific Daylight Time (PDT) is the daylight saving offset on the US/Canada Pacific coast, 7 hours behind UTC.

Countries in PDT
United States (Pacific)Canada (British Columbia)Mexico (Baja California)
Major Cities in PDT
Los AngelesSan FranciscoSeattleVancouverPortland
Key Facts about PDT
  • •PDT aligns with MST at UTC-07:00.
  • •Tech company earnings calls often reference PDT/PST times.
Daylight Saving:Yes – switches to PST
Learn more about PDT on Wikipedia

AST – Atlantic Standard Time

UTC-04:00

Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.

Countries in AST
Canada (Atlantic provinces)Puerto RicoUS Virgin IslandsDominican RepublicVenezuelaBoliviaBarbadosTrinidad and Tobago
Major Cities in AST
HalifaxSan JuanSanto DomingoCaracasLa PazFrederictonCharlottetown
Key Facts about AST
  • •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.
Daylight Saving:Yes – switches to ADT
Learn more about AST on Wikipedia

Understanding the +3h Gap: PDT vs AST

PDT runs on Pacific Daylight Time (PDT) at UTC-07:00. AST runs on Atlantic Standard Time (AST) at UTC-04:00. That puts PDT 3 hours ahead of AST — a difference of +3h at the current offsets.

In practice, when it is 9:00 AM in PDT it is 12:00 PM in AST. Midnight in PDT is 3:00 AM in AST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

PDT to AST time conversion table

PDT (PDT)AST (AST)Day
12:00 AM3:00 AMsame day
6:00 AM9:00 AMsame day
7:00 AM10:00 AMsame day
8:00 AM11:00 AMsame day
9:00 AM12:00 PMsame day
12:00 PM3:00 PMsame day
3:00 PM6:00 PMsame day
5:00 PM8:00 PMsame day
6:00 PM9:00 PMsame day
9:00 PM12:00 AMnext day

Why people convert PDT to AST time

  • Scheduling a call from PDT to AST: a 10:00 AM start in PDT lands at 1:00 PM in AST, so you can confirm the slot without doing the arithmetic yourself.
  • Finding shared working hours: both PDT and AST are inside the 9-to-5 working day between 9:00 AM and 2:00 PM PDT time (12:00 PM–5:00 PM AST). That is roughly 5 hours of usable overlap.
  • Coordinating a PDT-based team with AST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
  • Always state the zone abbreviation, not just the hour. "3:00 PM PDT" is unambiguous; "3 PM" across a +3h gap is not.
  • Block 9:00 AM–2:00 PM PDT as the recurring meeting window if you work primarily from PDT and need AST colleagues present.

About PDT (Pacific Daylight Time)

Pacific Daylight Time (PDT) is observed from March to November on the Pacific coast. During PDT, the west coast is 7 hours behind UTC and only 2 hours behind the east coast's EDT.

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 PDT and AST

Both PDT and AST sit inside the 9 AM – 5 PM working day between 9:00 AM–2:00 PM PDT, which is 12:00 PM–5:00 PM AST. That gives roughly 5 hours of shared time — the safest window for a live call or meeting.

Business hours overlap

PDT and AST share 5 hours of working-hours overlap (9:00 AM–2:00 PM PDT), so scheduling a live meeting is straightforward.

PDT is 3 hours ahead of AST (PDT UTC-07:00 → AST UTC-04:00). The shared working window is 9:00 AM–2:00 PM PDT. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

PDT

☀ Currently in DST

Standard: UTC-08:00 · DST: UTC-07:00

Clocks fall back on Sun, Nov 1, 2026

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:

⏳
History of Timekeeping
From sundials to atomic clocks - 5000 years of measuring time
🌍
How Time Zones Work
UTC, offsets, and why zones don't follow straight lines
☀️
Daylight Saving Time
DST dates, which countries observe it, and the ongoing debate

Frequently Asked Questions

What is the time difference between PDT and AST?

PDT (PDT, UTC-07:00) is 3 hours ahead of AST (AST, UTC-04:00). The gap is currently +3h.

How do I convert PDT time to AST time?

Add +3h to PDT local time. For example, 9:00 AM in PDT is 12:00 PM 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 +3h offset from PDT.

What is the best time to call AST from PDT?

Call between 9:00 AM and 2:00 PM PDT — that maps to 12:00 PM–5:00 PM AST and keeps both parties inside the working day.

Which is ahead, PDT or AST?

PDT is 3 hours ahead of AST. When it is 12:00 PM in PDT it is 3:00 PM in AST.

Does daylight saving time affect the PDT–AST difference?

Neither zone observes daylight saving time, so the +3h offset between PDT and AST is fixed all year.

Which other cities share PDT's time zone?

PDT also covers Los Angeles, San Francisco, Seattle, Vancouver, Portland.

Which countries use PDT, PDT's zone?

PDT is used in United States (Pacific), Canada (British Columbia), Mexico (Baja California).

Is there a day difference between PDT and AST?

Not normally. The +3h gap only pushes the date over for late-evening times.

What is the time difference between PDT and AST?

AST is +3h from PDT.

What timezone is PDT in?

PDT operates on its local timezone.

What timezone is AST in?

AST operates on its local timezone.

Which countries use PDT (Pacific Daylight Time)?

PDT is used in United States (Pacific), Canada (British Columbia), Mexico (Baja California).

Does PDT observe daylight saving time?

Yes, PDT switches to PST during summer months.

What are some interesting facts about PDT?

PDT aligns with MST at UTC-07:00. Tech company earnings calls often reference PDT/PST times.

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 PDT, what time is it in AST?

When it is 12:00 AM (midnight) in PDT (PDT), it is +3h later in AST (AST).

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