The Moon this month · UTC+8
December 1980 moon phases
New moon
Lunar 11/1
First quarter
Lunar 11/9
Full moon
Lunar 11/16
Last quarter
Lunar 11/23
Calculated phase moments use fixed UTC+8. A lunar day number and a Moon phase describe different things. How they fit together →
Light, not shadow
Why the shape changes
The Moon reflects sunlight. As it travels around Earth, we see different portions of its sunlit half; Earth’s shadow is involved in lunar eclipses, not the ordinary phase cycle.
New moon
The sunlit side faces away from us. Modern Chinese lunar months begin on the civil day containing new moon.
Compare this month’s dates ↑Waxing crescent
The visible crescent grows after new moon. Look for it in the western sky after sunset.
Compare this month’s dates ↑First quarter
Half the visible disk is lit. Quarter describes progress around the cycle, not how much of the disk is bright.
Compare this month’s dates ↑
Waxing gibbous
More than half of the disk is bright and the illuminated portion is still growing.
Compare this month’s dates ↑Full moon
The bright face points toward Earth. Its calculated date need not be the fifteenth lunar day.
Compare this month’s dates ↑
Waning gibbous
The illuminated portion shrinks after full moon, during the second half of the cycle.
Compare this month’s dates ↑Last quarter
Half the disk is lit again, this time waning. Third quarter is another name for this phase.
Compare this month’s dates ↑
Waning crescent
A narrowing crescent appears in the morning sky before the next new moon.
Compare this month’s dates ↑One sky, two ways to count
A lunar date is not a phase measurement
Months have numbered days
A lunar month has 29 or 30 calendar days. Its first day is tied to new moon, but its numbered days are whole civil dates—not equal steps in the Moon’s motion. A full moon can fall after lunar day fifteen.
Convert a Gregorian date →Phases have moments
New moon, the two quarters and full moon each have a calculated instant. Here they are placed on civil dates in UTC+8. A date containing one of those moments carries that phase label; other dates use the intervening waxing or waning phase.
Calendar and phase conventions →The Sun keeps the seasons
Lunar months alone drift through the seasons. The Chinese calendar also follows the Sun through its 24 terms, including the solstices and equinoxes. Solar branch months and lunar months therefore have different boundaries.
Explore the solar-term cycle →Moonlight and observance
The festival date and the Moon
Lantern Festival
The fifteenth day of lunar month one marks the first full-moon season of the new year. Its calendar date is fixed by the lunar day, not by the instant of astronomical full moon.
Mid-Autumn Festival
Families gather on lunar 8/15 for reunion, mooncakes and moon-viewing. Compare the festival’s date with the phase calendar when planning an evening outdoors.