In the United Stateswhile most states adjust their clocks twice a year to better utilize them daylighta select number of people have chosen not to participate in this practice.

Although daylight saving time (DST) is widely practiced, some states and territories have chosen to remain on standard time year-round.

Which states do not observe daylight saving time?

• Hawaii: This island nation, known for its tropical climate and geographic isolation, does not observe daylight saving time. Due to its proximity to the equator, the variation in daylight hours throughout the year is minimal, eliminating the need to adjust the clock.
• Arizona (except the Navajo Nation): Arizona has decided not to participate in daylight saving time due to its extremely warm climate. By not moving the clocks forward or backward, the state minimizes heat exposure during the hottest parts of the day, resulting in lower energy consumption for cooling. It is notable that the Navajo Nation, which spans parts of Arizona, Utah and New Mexico, does observe daylight saving time, unlike the rest of the state.

US territories that don’t change their clocks

• Puerto Rico: As a Caribbean region, Puerto Rico lies at a latitude similar to Hawaii, where variation in daylight duration is minimal throughout the year. Therefore, it does not follow daylight saving time.
• Guam: This American territory in the Pacific Ocean also stays on standard time all year round. As in other island areas, daylight hours do not vary enough to justify changing the clocks.
• American Samoa: Located in the South Pacific, this US territory follows a similar pattern to Guam and Puerto Rico and remains on standard time without clock adjustments.
• US Virgin Islands: Located in the Caribbean, these islands also avoid daylight saving time due to the minimal variation in daylight hours.

Reasons behind not implementing daylight saving time

The states and territories that choose not to observe summer time do this for practical and geographical reasons. In areas near the equator, such as Hawaii, Puerto Rico and Guam, the variation in sunlight throughout the year is so small that adjusting the clock provides little benefit.

In the case of Arizona, the main reason is climate. During the summer months, temperatures in the state can be extremely high. Maintaining standard time reduces heat exposure and the need for air conditioning, which in turn reduces energy consumption.

The Navajo Nation: An Arizona Exception

Interestingly, while Arizona as a whole does not observe daylight saving time, the Navajo Nation, which covers parts of Arizona, Utah and New Mexico, does. This exception exists because the Navajo Nation has chosen to follow daylight saving time to maintain consistency with other parts of its territory outside of Arizona and to observe the time change.

Future perspectives on summer time

Although some states and territories have opted out of daylight saving time, the debate over its usefulness remains a topic of national debate. In recent years, there have been moves in several states to make daylight saving time permanent, although such changes require federal approval.

The diversity in the application of daylight saving time in the United States reflects the different needs and geographic circumstances of the states and territories. In the future, we may see more exceptions or even a national shift in the way time is managed across the country.