Moon phases in 2026: reading the calendar and checking October

Instants versus civil days

The lunar phases – New Moon, First Quarter, Full Moon, and Last Quarter – are defined by precise instants when the Sun-Earth-Moon geometry reaches specific positions. These moments are recorded in Coordinated Universal Time (UTC).

When the instant occurs, each region of the planet translates it into the corresponding civil date for its time zone. Therefore, the same phase can appear on two different days in opposite time zones, such as the start of the Full Moon at 02:00 UTC being 22:00 of the previous day in UTC-4.

The four main moments

The four main phases mark reference points in the cycle. Waxing and waning describe increasing and decreasing illumination. At quarters, about half the visible disc is lit; its apparent right, left or tilted orientation depends on the observer’s location and orientation. Do not use that appearance as a universal visual rule.

Applying to October 2026

To check the lunar phase for October, locate in the table the UTC instant of each phase that falls between 1 and 31 October. Then, convert each instant to the time zone of your region (e.g., UTC-3 for Brasília). The resulting civil day will be the one that appears in the local lunar calendar.

If the instant occurs near local midnight, check whether the date changed before or after conversion; this avoids confusion such as assigning the Full Moon to the 15th when, in the chosen time zone, it occurred at 23:30 on the 14th.

Step-by-step to read the October lunar calendar

1. Consult the 2026 lunar phases table and note the UTC instants of New, First Quarter, Full, and Last Quarter that fall in October.
2. Determine the time zone of your location (e.g., UTC-3).
3. Convert each UTC instant to local time, adjusting days when the conversion crosses midnight.
4. Record the resulting civil date next to the corresponding phase; this will be the date that appears in your lunar calendar.
5. Use the sequence of the four phases to estimate the intermediate phases (waxing or waning) throughout the month.

Major phases in 2026

Calculated with Astronomy Engine, shown in UTC and America/Recife (UTC−3). October and the other months are included. These are astronomical instants, not predictions of ritual effects.

Sources and further reading

• NASA Science — Moon Phases