Abbreviations: Time zones

On this page

• General information
• Standard time zones
• Time zones during daylight saving time
• Short form time zones
• Time zones paired with specific times
• Additional information

General information

Canada spans six geographical time zones. Several Canadian provinces have stopped changing the clocks in the spring and fall and have created jurisdictional time zones such as Alberta Time. This writing tip, however, focuses on the geographical time zones.

Standard time zones

The six geographical time zones that Canada spans, and their abbreviations, are listed below.

• Newfoundland Standard Time (NST)
• Atlantic Standard Time (AST)
• Eastern Standard Time (EST)
• Central Standard Time (CST)
• Mountain Standard Time (MST)
• Pacific Standard Time (PST)

Time zones during daylight saving time

In some places, the clocks are set ahead one hour in the spring. From March to November, daylight saving time (DST) is in effect in those time zones.

• Newfoundland Daylight Time (NDT)
• Atlantic Daylight Time (ADT)
• Eastern Daylight Time (EDT)
• Central Daylight Time (CDT)
• Mountain Daylight Time (MDT)
• Pacific Daylight Time (PDT)

Short form time zones

There’s a trend toward omitting the words Standard and Daylight in the names of time zones so that time-sensitive material doesn’t need to be updated when the clocks are turned forward and back. In the short form, the word time is usually lowercased.

• Newfoundland time (NT)
• Atlantic time (AT)
• Eastern time (ET)
• Central time (CT)
• Mountain time (MT)
• Pacific time (PT)

Time zones paired with specific times

When no specific time is given, time zones are written out in full. But when a specific time is given, time zones are abbreviated. Note that in the abbreviations for time zones, capitals are used, without periods.

• 4:30 p.m. ESTE S T
• 7:15 a.m. NDTN D T

These abbreviations may be used with either the 12-hour or the 24-hour system.

• The historical interpreters at Louisbourg are on duty from 9:30 a.m. to 5:30 p.m. ADTA D T.
• The sun will rise over Souris, P.E.I., at 06:47 ASTA S T tomorrow.

Additional information

• Standard time, daylight saving time