One orbit · changing light
Moon phases explained
A Moon phase describes the illuminated fraction of the lunar disc visible from Earth. The cycle is continuous; the eight familiar names divide it into useful calendar sections.
The eight common Moon phases
- New Moon
The sunlit half faces away from Earth, leaving the near side dark.
- Illumination
- 0–4%
- Calendar span
- About 3.7 days in this eight-part calendar; exact new Moon is one instant.
- Best visibility
- It rises and sets close to the Sun and is normally lost in daylight.
- Traditional association
- Traditionally used for planning, clearing space and beginning a cycle.
Next new moon boundary: . Open date
- Waxing Crescent
A slim lit curve grows broader on successive evenings.
- Illumination
- 4–31%
- Calendar span
- About 3.7 days, from the first visible crescent towards first quarter.
- Best visibility
- Low in the western sky after sunset, setting later each evening.
- Traditional association
- Often associated with first steps, sowing and building momentum.
Next waxing crescent boundary: . Open date
- First Quarter
Half of the visible disc is lit at the exact quarter.
- Illumination
- 31–69% (50% at the exact quarter)
- Calendar span
- About 3.7 days as a phase label; the 90-degree quarter is an instant.
- Best visibility
- Rises around midday, stands high near sunset and sets around midnight.
- Traditional association
- Traditionally linked with decisions, action and overcoming resistance.
Next first quarter boundary: . Open date
- Waxing Gibbous
More than half is illuminated and the bright area is still growing.
- Illumination
- 69–96%
- Calendar span
- About 3.7 days on the approach to full Moon.
- Best visibility
- Visible from afternoon through much of the evening and after midnight.
- Traditional association
- Often used as a prompt to refine, prepare and bring work towards completion.
Next waxing gibbous boundary: . Open date
- Full Moon
The near side is almost completely illuminated, brightest at the exact opposition.
- Illumination
- 96–100%
- Calendar span
- About 3.7 days in the calendar label; exact full Moon is one instant.
- Best visibility
- Rises near sunset, crosses the sky overnight and sets near sunrise.
- Traditional association
- Traditionally associated with completion, attention and harvest.
Next full moon boundary: . Open date
- Waning Gibbous
More than half remains lit, but the bright fraction shrinks each day.
- Illumination
- 69–96%
- Calendar span
- About 3.7 days after full Moon.
- Best visibility
- Rises during the evening and remains prominent in the morning sky.
- Traditional association
- Often linked with reviewing, sharing and reducing what is no longer needed.
Next waning gibbous boundary: . Open date
- Last Quarter
Half of the disc is lit at the exact 270-degree quarter while waning.
- Illumination
- 31–69% (50% at the exact quarter)
- Calendar span
- About 3.7 days as a phase label; the exact quarter is an instant.
- Best visibility
- Rises around midnight, is high near dawn and remains visible into morning.
- Traditional association
- Traditionally used for pruning, reassessment and finishing practical work.
Next last quarter boundary: . Open date
- Waning Crescent
A narrowing crescent approaches the dark new-Moon alignment.
- Illumination
- 4–31%
- Calendar span
- About 3.7 days before the next new Moon.
- Best visibility
- Low in the eastern sky before sunrise and harder to see each morning.
- Traditional association
- Often associated with rest, maintenance and preparing for the next cycle.
Next waning crescent boundary: . Open date
01
Waxing, waning and illumination
Waxing means the illuminated fraction is increasing; waning means it is decreasing. Illumination is a percentage, while phase angle records the Moon's position in the cycle. Two dates can have similar illumination but opposite directions.
02
Using the phase names in a calendar
The monthly Moon calendar calculates a phase at local noon for each date. Exact new, quarter and full Moon instants appear separately in the phase schedule. For the live state, open today's Moon phase.