The time changes twice a year in most countries that observe daylight saving time (DST). DST is a practice of advancing clocks forward one hour during the summer months, and then back again in the fall. This is done to make better use of daylight hours, and to save energy.

In the United States, DST begins on the second Sunday in March and ends on the first Sunday in November. So, in 2023, DST will begin on March 12 and end on November 5.

The time change occurs at 2:00 AM local time. So, on Sunday that DST begins, you will need to set your clocks forward one hour before going to bed on Saturday night. And, on the Sunday that DST ends, you will need to set your clocks back one hour before going to bed on Saturday night.

There are a few exceptions to the general rule of when the time changes. For example, Arizona and Hawaii do not observe DST. And, some states in the United States, such as Indiana and Kentucky, have different rules for when DST begins and ends.

If you are unsure about when the time changes in your area, you can check with your local government or the National Institute of Standards and Technology (NIST).

Here are some of the reasons why countries observe DST:

• To make better use of daylight hours. During the summer months, the days are longer, so people can enjoy more sunlight in the evening. This can lead to a decrease in energy consumption, as people are less likely to use artificial light in the evening.
• To save energy. By advancing clocks forward one hour during the summer months, people are more likely to be active during daylight hours and less likely to use artificial light. This can lead to a decrease in energy consumption.
• To improve safety. DST can improve safety by increasing visibility during the morning and evening commutes. This is because there is more daylight during these times, which can make it easier for drivers to see other vehicles and pedestrians.

There are also some potential drawbacks to DST:

• Disruption to sleep schedules. The time change can disrupt sleep schedules, as people may go to bed and wake up one hour earlier or later than usual. This can lead to fatigue and decreased productivity.
• Increased risk of accidents. The time change can increase the risk of accidents, as people may be more tired or less alert during the first few days after the change.
• Disruption to businesses. The time change can disrupt businesses, as they may need to adjust their hours or operations. This can lead to inconvenience for customers and employees.

Overall, the benefits of DST outweigh the drawbacks. However, it is important to be aware of the potential drawbacks and to take steps to mitigate them. For example, you can try to go to bed and wake up at the same time each day, even on the days that the time changes. You can also avoid driving or operating machinery for the first few days after the time change.