About Lock the Clock
What this tool is, how it works, and where the numbers come from.
In March 2026 the U.S. House of Representatives passed the Sunshine Protection Act by a vote of 308–117. The bill would end the twice-a-year clock change and put the entire country on permanent daylight saving time. It still needs to pass the Senate and be signed by the President before it becomes law.
“Permanent daylight time” is easy to say and surprisingly hard to picture. What would it actually do to your mornings and evenings — in January, in your town? This tool answers that concretely: enter a zip code, drag through the year, and compare the sunrise and sunset you get under today’s law against the sunrise and sunset you’d get under the bill.
How it works
- Sun position: Sunrise and sunset are computed with the National Oceanic and Atmospheric Administration (NOAA) solar-position equations, using the latitude and longitude for your region and the day of year you select.
- Location: Your zip’s first three digits map to a representative point for that postal region, drawn from public U.S. postal data. That’s enough for accurate sun times (they change by only seconds across a three-digit zip area) and it means your exact zip never has to leave your browser.
- Time zone: Your state determines the time zone and whether it currently observes daylight saving time. States split across two zones use the zone covering most of their population, which the tool notes.
Frequently asked questions
Is this an official government tool?
No. This is an independent educational project. It is not affiliated with Congress, NOAA, or any government agency, and it is not legal or policy advice.
Is permanent daylight saving time the law now?
Not yet. As of the last update, the Sunshine Protection Act had passed the House only. It has not passed the Senate and has not been signed into law, so nothing about your clocks has changed. The tool shows what would happen if it does become law.
How accurate are the sunrise and sunset times?
The NOAA equations are accurate to about a minute for locations in the continental U.S. Because the location is the center of your three-digit zip region rather than your exact street, times can differ by a few seconds from a pinpoint calculation — not enough to change what you see.
Why doesn’t it show my exact city?
The tool groups locations by the first three digits of the zip code and shows a representative city for that region. This keeps the whole lookup inside your browser with no server call, so it stays fast and private even under heavy traffic.
Would the bill change my summer daylight?
No. From mid-March to early November the country is already on daylight time, so those days look identical either way. The entire difference is in the winter months: darker mornings and an extra hour of evening light, and no “spring forward” or “fall back.”
Is my zip code stored or sent anywhere?
No. It’s processed entirely in your browser and never transmitted. See the Privacy Policy for details.