Why Matariki falls on a different day each year

Wondering why the Matariki public holiday is being observed on July 14 this year when it fell on June 24 last year?

This is because Matariki follows the traditional Māori lunar calendar system as opposed to the solar calendar system.

One of the major differences is the solar year that we follow is 365 and a quarter days long whereas the lunar calendar system is 354 days - a difference of 11 days.

That can add up to a 33-day difference over three years.

Many cultures across the world do intercalation.

This means an extra month is dropped into the calendar system every three or so years so that the lunar calendar system reconciles with the sun.

In the maramataka (the Māori lunar year), the extra month is added after Pipiri (June) every third year. The name of the extra month is Ruhanui.

Astronomy academic Rangi Mātāmua said this was taken into account when the decision came to set the Matariki dates.

In a Facebook Live posted on May 23, Mātāmua said Matariki is generally really high in the morning sky in the first year after that reconciliation.

Then in the second year, like how it was last year, it tends to be lots lower in the sky.

Mātāmua said he celebrates Matariki in the Tangaroa phases or the last quarter of the lunar phases.

This is when we celebrate the major atua Māori (Māori gods and spirits), the atua who supply us with food. Matariki is very much connected to the kai we receive throughout the year.

To sum it up, the date of Matariki will change from year to year, however, it will always land in June or July.

2024 - 28 June

2025 - 20 June

2026 - 10 July

2027 - 25 June

2028 - 14 July