Daylight saving time began early Sunday morning, but Arizonans didn’t need to adjust their clocks — only how they track time in the rest of the country.

Arizona does not observe daylight saving time, remaining on Mountain Standard Time year-round and avoiding the annual shift of losing and gaining an hour.

The rest of the country, including parts of the Navajo Nation within Arizona, observes daylight saving time. On Sunday at 2 a.m., clocks moved forward one hour to 3 a.m., a change that will remain in effect until standard time returns in November.

The Navajo Nation spans Arizona, Utah, and New Mexico, and observes daylight saving time to ensure the same time zone exists for all members.

Due to Arizona’s extreme heat, the state opted out of daylight saving time to allow residents to experience cooler evening temperatures earlier than the rest of the country.

Arizona initially observed daylight saving time until 1918, but the state made the change permanent in 1968, according to the Secretary of State’s website.

President Donald Trump in December, before he was sworn in, suggested eliminating daylight savings time, labeling it as “inconvenient” and costly to the U.S., as he wrote on social media Truth Social, which the president owns.

On Thursday, President Trump said daylight savings time is “a very much 50/50 issue,” and avoided any further advocation on either side of the debate.

The Arizona Republic’s Olivia Rose and USA TODAY’s Anthony Robledo contributed to this article.

Reach reporter Rey Covarrubias Jr. at [email protected]. Follow him on X, Threads and Bluesky @ReyCJrAZ.