MSTTime.nowMountain Standard Time

AST Time Now

Saturday, October 17, 2026
Time zone
Atlantic Standard Time (AST)
UTC offset
UTC−4
Daylight saving
Not observed
Sunrise / sunset
06:18 / 18:01

AST is in use right now in Atlantic Time (UTC−4).

AST is 2 hours ahead of MDT (Mountain Standard Time).

AST time zone

Atlantic Time

Atlantic Standard Time (AST)

IANA: America/Puerto_Rico · UTC−4

Daylight saving time in AST

AST does not use daylight saving time. The offset stays UTC−4 all year.

Sunrise and sunset in AST today

Sunrise 06:18 · Sunset 18:01

Daylight 11h 43m · Solar noon 12:09

What time zone is AST in?

AST is on Atlantic Time (AST, UTC−4). The IANA identifier is America/Puerto_Rico.

Does AST observe daylight saving time?

No. AST keeps UTC−4 all year, so its time difference with places that do change their clocks shifts by an hour twice a year.

Time in AST vs major world cities

CityLocal timeDifference from AST
New York Satsame time
Los Angeles Sat3 hours behind
London Sun5 hours ahead
Paris Sun6 hours ahead
Dubai Sun8 hours ahead
Mumbai Sun9.5 hours ahead
Singapore Sun12 hours ahead
Tokyo Sun13 hours ahead
Sydney Sun15 hours ahead
Johannesburg Sun6 hours ahead
São Paulo Sat1 hour ahead
Chicago Sat1 hour behind

October 2026 calendar for AST

MonTueWedThuFriSatSun
1234
567891011
12131415161718
19202122232425
262728293031

Frequently asked questions about AST

What time zone is AST in?
Atlantic Time (AST), UTC−4; IANA zone America/Puerto_Rico.
Does AST have daylight saving time?
No, it stays on UTC−4 all year.

More like AST

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Guides on AST