PDT to AST
+4hPDT
PDTSOURCEAST
ASTGreen 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.
PDT – Pacific Daylight Time
UTC-07:00Pacific Daylight Time (PDT) is the daylight saving offset on the US/Canada Pacific coast, 7 hours behind UTC.
- •PDT aligns with MST at UTC-07:00.
- •Tech company earnings calls often reference PDT/PST times.
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: PDT and AST
PDT (Pacific Daylight Time) operates on the Pacific Daylight Time (UTC-07:00). AST (Atlantic Standard Time) uses Atlantic Standard Time (UTC-04:00).
The time difference between PDT and AST is 240 minutes (+4h). When it's noon in PDT, it's 04:00 PM in AST.
Why Convert PDT to AST Time?
When planning a meeting or scheduling a call between PDT and AST, it's crucial to account for the 4-hour time difference. Whether you're coordinating with remote teams, calling family, or setting up an international conference, knowing the exact time in AST helps avoid missed connections.
Tip: When scheduling a meeting, always confirm the time zone with your counterpart in AST. The 4-hour difference can easily lead to confusion if not explicitly stated.
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
If you want to reach someone in AST during standard business hours (9 AM – 5 PM AST), the best time to call from PDT would be:
- AST 9:00 AM = PDT 05:00 AM
- AST 12:00 PM = PDT 08:00 AM
- AST 5:00 PM = PDT 01:00 PM
Business Hours Overlap
PDT and AST have a partial business hours overlap. The best window for meetings and calls is when both locations are in their working hours.
Ultimately, understanding the +4h difference between PDT and AST empowers you to coordinate better. Whether for business or personal reasons, this tool ensures you're always on time.
🕐 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:
Frequently Asked Questions
What is the time difference between PDT and AST?
AST is +4h 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 +4h later in AST (AST).
Related Developer Tools
Explore more tools that work great with timezone conversions for international teams: