In the United StatesWhile most states adjust their clocks twice a year to better align with daylight hours, a select number of states and territories have chosen not to follow this practice. These exceptions remain in effect standard time year-round, avoiding the semi-annual clock changes that most of the country experiences.

Although summer time (DST) is generally accepted, practical and geographical factors are leading some states and territories to opt out. Whether due to minimal variation in daylight hours or unique climate conditions, these areas have experienced little to no benefit from observing daylight saving time.

States that do not observe daylight saving time

Hawaii
Hawaii, 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, making clock adjustments unnecessary.

Arizona (except the Navajo Nation)
Arizona has opted for daylight saving time, largely because of its extremely warm climate. By not moving the clocks forward or backward, Arizona reduces exposure to the hottest part of the day, leading to lower energy use for air conditioning. However, the Navajo Nation, which includes 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
Because Puerto Rico is a Caribbean region, its proximity to the equator means it experiences little variation in daylight hours throughout the year. For this reason, Puerto Rico does not observe daylight saving time.

Guam
This American territory in the Pacific Ocean also stays on standard time all year round. Like other island areas, Guam experiences minimal daylight variation, making clock changes unnecessary.

American Samoa
Located in the South Pacific, American Samoa follows a similar pattern to Guam and Puerto Rico, keeping standard time all year round.

US Virgin Islands
The U.S. Virgin Islands, located in the Caribbean, also does not observe daylight saving time due to the minimal change in daylight hours throughout the year.

Reasons not to observe daylight saving time

The states and territories that choose to forgo daylight saving time often do so for geographic or practical reasons. For areas near the equator, such as Hawaii, Puerto Rico, and Guam, there is little variation in daylight hours throughout the year, so adjusting the clocks offers little benefit.

In Arizona, the main reason is the climate. Summer temperatures in the state can be extremely high, and keeping standard time minimizes heat exposure during peak hours, reducing demand for air conditioning and lowering energy consumption.

Summary of states and territories that do not observe daylight saving time

The Navajo Nation: An Arizona Exception

Interestingly, although most of Arizona does not observe daylight saving time, the Navajo Nation do. This exception exists because the Navajo Nation straddles Arizona, Utah, and New Mexico, where daylight saving time is observed. The Navajo Nation chooses to maintain consistency across its territory, including areas outside of Arizona.

Future prospects for daylight saving time

Although some states and territories have chosen not to participate in daylight saving time, the debate over its usefulness remains a national topic. In recent years, there have been increasing moves in certain states to make daylight saving time permanent, although such changes require federal approval.

The varied application of daylight saving time in the US reflects the different needs and geographic conditions of the states and territories. As this conversation continues, we may see even more exceptions or even a broader national shift in the way time is managed across the country.