Why It Matters

Nineteen states have enacted permanent daylight saving time (DST) laws, but those laws cannot take effect without congressional authorization, according to a new Congressional Research Service (CRS) report. ​

States may already choose permanent standard time under existing federal law without waiting for Congress, but permanent DST requires new congressional action.

The Big Picture

The authority to change DST observance rests solely with Congress, even as a majority of states have moved to lock in one time year-round. Of the 50 states and the District of Columbia, 47 states and DC have introduced legislation proposing some form of permanent year-round DST, while 42 states have introduced legislation to establish permanent year-round standard time. Eight states have not introduced permanent standard-time legislation.

The Uniform Time Act of 1966, as amended, allows states to exempt themselves from observing DST, meaning a state can adopt permanent standard time without waiting for Congress. Permanent DST enactments, by contrast, would go into effect only "if and when such action is allowed by Congress," the report states. That asymmetry is the central legal constraint the report documents: one path is open to states unilaterally, the other is not.

DST begins on the second Sunday in March and ends on the first Sunday in November, with those dates set in 15 U.S.C. § 260a. American Samoa, most of Arizona, Guam, Hawaii, the Northern Mariana Islands, Puerto Rico and the U.S. Virgin Islands do not observe DST.

The Bottom Line

The House passed H.R. 139, the Sunshine Protection Act of 2025, on July 14, and the bill was referred to the Senate Committee on Commerce, Science, and Transportation on July 15. The bill would make DST the permanent national standard. S. 29, also titled the Sunshine Protection Act of 2025, was read twice and referred to the same committee on Jan. 7, 2025.

Both measures now sit in Senate committee with no vote scheduled. If the Senate does not act, the 19 state permanent-DST enactments remain contingent and without legal effect.

Access the Legis1 platform for comprehensive political news, data, and insights

Spot something wrong? Report an issue with this article