Free · private · calculated on your device
Full Moon today or tomorrow?
Compare the same lunar phase event across time zones and understand why different calendars can display different dates.
A phase of the Moon happens at one calculated instant, but calendars label that instant using local dates and clocks. A Full Moon near midnight can therefore appear on different dates in two places without either calendar being wrong.
No name, email or account is needed. Your details stay on your device. Use the clear button to remove entered details and results.
How to use this tool
Choose the event year in UTC and an event; a local date near the year boundary can fall in the adjacent year. Compare its UTC instant with your selected time zone and other reference zones. You can use the calendar download tool to keep the events in an app that displays your local time automatically.
How to read the result
First compare the underlying UTC timestamps. If those agree, a difference in civil date can be explained by time zones. If the timestamps differ substantially, check the event definition and calculation method as well; changing a display zone does not move the astronomical event.
Method and limits
This compares calculated lunar phase instants, not the date on which you personally see a fully illuminated-looking Moon. Visibility depends on the local horizon and observing conditions. A calendar date is not a separate regional Full Moon.
The calculation uses Astronomy Engine 2.1.19 and, where applicable, the project’s offline time-scale and house geometry modules. Mathematical positions and traditional interpretation remain separate.Read the full methodology.