A lunisolar system tracks:

Lunar cycles (moon phases → months)

Solar cycle (sun’s annual path → seasons)

Individual days as the lived rhythm that ties them together

A lunisolar calendar reconciles the mismatch between:

12 lunar months ≈ 354 days

Solar year ≈ 365.24 days

That ~11-day gap must be corrected, usually with an intercalary (leap) month.

Day-keeping refers to how a culture defines:

Lunisolar day-keeping is about harmonizing three rhythms:

The Earth’s rotation (day) The Moon’s orbit (month) The Earth’s orbit (year)

It’s a three-body temporal system.

In a Metonic lunisolar system, the moon’s phases and the solar year are synchronized over a 19-year cycle. Here’s the idea: Each year, you measure 12 lunar months, which is about 354 days. That’s about 11 days short of a solar year. So, over time, the lunar calendar drifts. To realign, you insert an extra “leap” month in 7 of those 19 years. By the end of the 19-year cycle, the lunar and solar years come back into alignment. The days thus stay anchored to both the moon’s phases and the seasons, creating a beautiful balance over the long term.

Let’s look at one of our Lunisolar Calendars to learn more about how they specifically work.

Galdercraft Anglo-Saxon Runic Calendar

Galderskill Norse Younger Futhark Calendar

Cnóbha Celtic Ogham Calendar