The planet of earth on which we live is massive. It comprises different parameters such as revolution, rotation etc.
When a specific part or certain place experiences daytime, a particular interest or certain areas experience nighttime. And those time zones are of several types and are categorized by many terms.
Key Takeaways
- UTC stands for Coordinated Universal Time, a time standard used worldwide, while PDT stands for Pacific Daylight Time, used in the Pacific Time Zone of North America.
- UTC is a time standard based on atomic clocks, while PDT is a time zone based on the Earth’s rotation relative to the Sun.
- UTC is used for international aviation, navigation, weather forecasting, and satellite operations, while PDT is used in the western United States and Canada during the summer months.
UTC vs PDT
PDT (Pacific Daylight Time) has an offset of UTC – 7:00, or UTC is 7 hours ahead of Pacific daylight time. While UTC (Coordinated Universal Time) is a time zone that is acknowledged around the world. Atomic clocks serve as UTC’s foundation. It’s used for international aviation, navigation, etc.

The UTC, or the Coordinated Universal Time, was the first-ever time system/zone put forth to the world on 1 January 1960. Several modifications have been done ever since its inception.
In one of its revisions, leap seconds were introduced for feasible future time measurements. The CCIR, too, recommended several suggestions for improving this time system.
PDT, or The Pacific Time Zone, is the time zone that is seven hours behind the Universal Time Zone. Places like Western United States, Western Canada, and Western Mexico follow the Pacific Time Zone.
In Canada and the USA, Pacific Time Zone is also known as the Pacific Standard Time (PST) while observing time from early November to mid-March and is known as the Pacific Daylight Time (PDT) during mid-March to early November.
Comparison Table
Parameters Of Comparison | UTC | PDT |
---|---|---|
Full form | Coordinated Universal Time | Pacific Time Zone |
Time Difference | seven hours ahead | seven hours behind |
Effective since | 1 January 1960 | 2007 |
Unit/formula used to measure | atomic seconds | UTC-7 hours or PDT+ 7 hours |
Followed by countries/places | Entire world | Western USA, Western Mexico, Western Canada |
What is UTC?
UTC, also known as the Coordinated Universal Time, is a time zone followed by the entire world. It is the primary source of measuring time by which several countries rectify time and clocks.
This means that the Coordinated Universal Time or the Universal Time Coordinated was called Greenwich Mean Time before 1972. It has been effective since 1 January 1960.
Since its establishment, several modifications have been made to the Coordinated Universal Time (UTC). One of those revisions includes adapting leap seconds formulated for feasible future measurements and calculations based on time.
The CCIR, in one of its recommendations, stated that there must be a constant maintained between the frequencies and intervals of time, which should harmonize with the SI definition of the second.
Sir Sandford Flemming put forth the ideologies of global time zones, 24-hour clocks and prime meridian for precision in time measurement. After that, many evolving factors were witnessed in time measurement worldwide.
There exist several uses of Coordinated Universal Time (UTC). One of the most fundamental uses is that various countries operate their time using the Coordinated Universal Time as a primary reference source.
The Network Time Protocol synchronizes the time in devices like computers and uses the Coordinated Universal Time for reference. Other than that, The Coordinated Universal Time is used in radio operations, the aviation industry for weather prediction and air traffic control.

What is PDT?
The Pacific Time Zone, or PDT, is the time zone that is seven hours behind the Coordinated Universal Time Zone (UTC). Western USA, Western Canada and Western Mexico are the countries that follow the Pacific Time Zone.
For observation of the standard time, seven hours are subtracted from the Coordinated Universal Time, or seven hours are added to the Pacific Time Zone. The Pacific Time Zone has been in effect since 2007 in the United States of America.
The Pacific Time Zone is divided into Pacific Daylight and Pacific Standard Time. It is referred to as the Pacific Standard Time from early November to mid-March, and it is referred to as the Pacific Daylight Time from mid-March to early November.
The Pacific Time Zone is a few hours ahead in some places time zones in the Western USA, Western Canada and Western Mexico, and it is also behind a few hours in some places time zones in the Western USA, Western Canada and Western Mexico.
Similar to such sorts, the Pacific Time Zone has independent divergences depending on the place, city, or state. Los Angeles city of the USA is the most prominent place in the Pacific Time Zone.

Main Differences Between UTC and PDT
- UTC, or the Coordinated Universal Time, is used for operating time worldwide. On the other hand, the Pacific Time Zone is used only in some countries.
- The Coordinated Universal Time has been in effect since 1920. On the other hand, the Pacific Time Zone has been in effect since 2007 in the USA.
- The Coordinated Universal Time does not fluctuate with change in months. On the other hand, the Pacific Time Zone fluctuates with changes in months.
- The Coordinated Time Zone has several applications worldwide. On the contrary, the Pacific Time Zone has uses in limited places worldwide.
- The largest city that follows the Pacific Time Zone is the city of Los Angeles in the USA and the country with the most time zones in the world, which follows the Coordinated Universal Time in France.