Full Moon September 2027: Harvest Moon

About the Harvest Moon

The full moon closest to the September equinox, which can fall in September or early October.

Its name comes from the extra evening light it gave farmers finishing the harvest. Around the equinox the angle of the ecliptic to the horizon is shallow, so the moon rises soon after sunset for several nights in a row. It is the only full moon name defined by the equinox rather than the month.

Watch the moonrise on the two or three evenings around the full date; the near-continuous dusk-to-moonlight transition is the effect farmers valued.

Lore

For centuries farmers relied on the Harvest Moon's extra evening light to bring in the crops after sunset. The effect is real: near the equinox the Moon's path meets the horizon at a shallow angle, so it rises soon after sunset for several nights in a row. Harvest festivals across the northern hemisphere, from Canadian Thanksgiving to the Mid-Autumn Festival, sit close to this moon.

Trivia

• The Harvest Moon can fall in September or early October; it is the only full moon defined by the equinox rather than the month.
• 'Shine On, Harvest Moon' was a 1908 vaudeville hit that is still recorded today.
• The Mid-Autumn Festival is held on the day of this full moon in the Chinese lunar calendar.