Corrections and Error Reports

What is worth reporting

• A clock that is wrong. A country or city showing the wrong local time, the wrong UTC offset, or the wrong daylight saving state for a date.
• A missing or wrong time zone. A country that uses a zone World Time Lab does not list, or a region shaded with a zone it does not actually keep.
• Sun or moon times that are well off. Ten minutes or more from a published almanac for the same coordinates, at a latitude outside the polar circles.
• A wrong place fact. A city in the wrong country, coordinates in the wrong place, a misnamed or misplaced state, province, or region.
• A wrong calendar entry. A public holiday on the wrong date, or one that does not exist in that country at national level.
• A wrong eclipse or season detail. A date, type, or visibility description that disagrees with the NASA tables.
• Broken pages. Layout that overflows or overlaps, a control that cannot be reached by keyboard, text that is unreadable in one theme, a link that goes nowhere.
• Wording that misleads. If a sentence on this site implies more precision or more authority than the data supports, that is a real defect and is treated as one.

What to include

Four things turn a report into a fix. Without them, most reports cannot be reproduced and quietly stall.

1. The page URL, copied from the address bar, including any query string.
2. The value World Time Lab showed you, exactly as printed, with the date and time you saw it and which time zone your own device is in.
3. The value you expected, in the same units and the same zone.
4. Your source, ideally an official one: a national almanac, a government gazette, the IANA time zone database announcement, the NASA eclipse tables. "My phone says otherwise" is a starting point, not a source.

Also useful, especially for anything visual: your browser and version, your operating system, and whether you were in light or dark theme. A screenshot settles most layout arguments in one step. The site version is printed in the header and footer, so include that too.

What happens next

1. Reproduce. The report is checked against the page and against the source you cited. If it cannot be reproduced, the operator of World Time Lab will say so rather than leaving it in limbo.
2. Classify.A defect in the site's own code or curated data is fixed here. A defect inherited from an upstream dataset is reported upstream and, where possible, worked around in the meantime. A documented limit is answered with a pointer to the methodology page, and if the page does not explain it clearly enough, the page gets improved.
3. Ship. Fixes go out with the next build. World Time Lab is a static site, so a correction reaches readers when a new version is published; the version number in the header tells you which build you are reading.
4. Record. Where a correction changes what a page asserts, the reviewed date on that page moves with it. Curated datasets carry their own verification stamp; the country to zone mapping currently reads July 2026.

There is no ticket queue and no promised turnaround. Reports are read by hand, and a precise one is answered long before a vague one.

Known limits that are not errors

These are documented consequences of the method, not defects. Reporting them is welcome, but the answer will be a link rather than a fix.

Sunrise or sunset differs by a minute or two

Sun times are computed to about a minute and displayed to the minute. Two sources using slightly different truncations of the same equations will disagree at that level. World Time Lab solves the crossing at a sun altitude of -0.833 degrees, the standard allowance for refraction and the solar disc; a source using a different convention will differ systematically.

Real sunrise happens at a different time than the page says

Sun times assume a flat, unobstructed horizon at sea level. A ridge to the east, a building, a valley, or standing on a hill can move the observed event by many minutes. Sea fog and unusual pressure or temperature change refraction beyond the standard allowance. Terrain is not modeled.

A city's coordinates are not your street

Each place uses one representative point. In a large metropolitan area, that point can sit many kilometers from you, which shifts sun times slightly and can even put you on the other side of a boundary.

Times near the polar circles look unstable

When the sun grazes the horizon, a small error in altitude becomes a large error in time, and a date can flip between a very long day and continuous daylight. World Time Lab labels midnight sun and polar night explicitly instead of printing a misleading time.

A holiday is on a different day where you live

Calendar holiday sets are country-level. States, provinces, cantons and emirates add their own; weekend substitution rules vary; and governments move dates by proclamation. Dates fixed by moon sighting or by a religious authority are announced locally and cannot be tabulated in advance with certainty. World Time Lab omits dates its source marks as estimated rather than guessing.

Your device shows a different offset than World Time Lab

World Time Lab reads the time zone database inside your own browser, so both should agree. If they do not, one of the two is usually stale: try updating the device. A genuine mismatch between World Time Lab's curated country to zone mapping and the current IANA rules is a real error and worth reporting.

The Seasons view disagrees with the weather outside

That view is climate classification plus the calendar, not a forecast. It has no knowledge of today's conditions and is not intended to.

Planet Lab results do not match a research paper

The simulator is an educational approximation with a zero-dimensional energy balance. It is validated against the real conditions of four solar system planets as a sanity gate, and it is not a climate model. Expert mode shows the equations it is actually using.

How updates are scheduled

• Time zone rules update continuously through your browser, with no release from this site required.
• The curated country to zone mapping is reviewed and stamped with the date of that review.
• Snapshot datasets (cities, administrative regions, climate grid, holiday tables) are regenerated from upstream by pinned build scripts when the upstream source publishes a meaningful change, or when a correction shows the snapshot is out of date.
• The eclipse catalog is extended from the NASA decade tables as the coverage window advances.
• Urgent factual errors are not held for a schedule. They go out as soon as they are verified and built.

The full detail of every source, its license, and its known limits lives on the methodology page. General questions that are not corrections belong on the contact page.