Difference between PST and PDT

By: | Updated: May-16, 2021

Time is the measurement of motion, that is, of the continuous change in the position of an object. It is the first dimension of space. Time is also a part of space, as we can imagine it as the fourth dimension. In addition to this, the world’s time zone is divided into 24 zones. These zones are separated by 15 degrees longitude. The “PST” and “PDT” are two such time zones. These are the abbreviations of “Pacific Standard Time” and “Pacific Daylight Time”.

Summary Table

PST PDT
PST is the time zone in which all the states of the Pacific Coast are situated PDT is the time zone which includes the whole of California
The PST is located between 114 and 120 degrees west longitude The PDT is located between 120 and 126 degrees west longitude

Definitions

 

Difference between PST and PDT

The “PST” is the time zone in which all the states of the Pacific Coast are situated. This zone is located between 114 and 120 degrees west longitude. The states which are located in this time zone are: Alaska, Washington, Oregon, California, Idaho, Montana, Nevada and Utah.

The “PDT” is the time zone which includes the whole of California. It is located between 120 and 126 degrees west longitude. This time zone follows daylight saving time from the first Sunday in April to the last Sunday in October. In addition to this, some other states of America like Arizona and Hawaii also follow daylight saving time during this period.

The time of the day is divided into two parts: the time of day and the time of night. The time during which a place receives daylight is called daytime and the period when it is dark is called nighttime. Daylight saving time refers to a practice where a region sets its clocks forward by one hour in order to save daylight during summer months. This is done by moving the clock forward by one hour. For example, if it is 7:00 p.m. on the first Sunday of April, then it becomes 8:00 p.m. The clocks are moved forward to this time so that there is an extra hour of daylight for outdoor activities in the evening. This also helps to reduce energy consumption as it reduces the need for artificial lighting during evenings and nights.

This practice was started during World War II by Germany to conserve energy during a period when fuel was scarce and its use was restricted by government regulations. As a result of this policy, some parts of Europe shifted their clocks forward by one hour to make better use of daylight hours for economic activities such as agriculture. The idea caught on and now it has become a common practice all over the world where many countries have adopted it permanently except for a few countries like Japan and Australia.

PST vs PDT

The “PST” and “PDT” are the time zones which have the same time during the summer. But during the winter, they have different times. To put it simply, the following shows the differences between these two time zones.

  1. The “PST” is used during the summer. This time zone includes all the states of the Pacific Coast. The “PDT” is used during the winter, and this time zone includes only California.
  2. During the summer, these two time zones have the same time which is 8 hours behind Greenwich Mean Time (GMT). But during the winter, they have different times as explained below:
  3. a) During daylight saving time (DST), which lasts from April to October, both of these time zones are an hour ahead of GMT.
  4. b) During standard time, which lasts from October to April, the “PST” is 8 hours behind GMT and the “PDT” is 7 hours behind GMT.
  5. The states that follow the “PST” are: Alaska, Washington, Oregon, California, Idaho, Montana and Nevada. The states that follow the “PDT” are: California and Arizona, and Hawaii.
  6. The DST in these two time zones starts on the first Sunday in April and ends on the last Sunday in October. The DST begins at 2 a.m. local time and ends at 2 a.m. local time.

Converting PST and PDT

We have seen above that the “PST” and “PDT” are two time zones which have the same time during the summer. But during the winter, they have different times.

First of all, we need to identify which of these two time zones is applicable for a particular date. For example, if we want to know what time it is in PDT on March 15, we will check what date it is on March 15 in PDT and then we will convert it into PST.

The next step is to convert the date from PDT to PST. This can be done by subtracting 8 hours from the PDT time. For example, if it is 2 PM in PDT on March 15, then it will be 10 AM in PST on March 15. Thus, we have seen that the time in “PST” is 8 hours behind the time in “PDT”. This means that the time in “PST” is 8 hours less than the time in “PDT”. So, the answer to the question “How do you convert PST to PDT?” is 8 hours.

Do you say PST or PDT?

Both these abbreviations are correct. The PST is used by most of the people and it is the official name of this time zone. It is also used in the state of Washington, whereas PDT is more common in California. As mentioned above, the name “Pacific Standard Time” was given to this time zone during World War II when there was a need to conserve energy. In the year 1966, the Congress of the United States passed a law which abolished daylight saving time and since then the whole of America follows this time zone.

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