Editorial policy

Our date information is built around clear rules, cited sources and visible limits.

How dates are checked

Federal holidays and observed-day conventions are checked against the Office of Personnel Management. Daylight saving rules follow the Department of Transportation. Full moon instants come from the U.S. Naval Observatory; sports dates are confirmed with the organizer.

Annual updates

Rule-based dates are generated for each calendar year. We recheck exceptional schedules, source links and dated editorial copy when refreshing the site. Lunar tables and event announcements are added only after checking their sources.

Coverage and confidence labels

Our current coverage register identifies which datasets are verified, rule-based, forward-looking planning estimates or dependent on local verification. It also records the years currently covered and the primary reference used.

Limitations and corrections

Local school, employer, bank, transit and state schedules vary. If a date or explanation looks wrong, please use the contact page to report it.

Who maintains this

Daymark is maintained by a small family from Missouri, not a large newsroom. That means fewer topics covered, but every one of them checked by hand against the source linked on its page. Read more on our about page.