Park City’s September skywatch: Full Corn Moon, lunar eclipse, and equinox

Photo: Photo by Sam

PARK CITY, UT — September delivers a tightly framed but meaningful sequence of celestial events for Summit County, according to the Farmers’ Almanac.

Full Corn Moon — Sept. 7

The full Corn Moon rises on Sunday, Sept. 7, 2025, reaching peak illumination at 12:09 p.m. Mountain Daylight Time. In most years, September’s full moon is known as the Harvest Moon—the one nearest the autumnal equinox. But in 2025, October’s full moon will fall closer to the equinox, leaving September’s to carry the Corn Moon name, a distinction that happens only occasionally.

Total Lunar Eclipse — Sept. 7 (Not Visible in North America)

Later that day, the moon will slip into Earth’s shadow during a total lunar eclipse lasting roughly 83 minutes, placing it among the longer eclipses of the year. For observers in Summit County, however, the event will remain out of reach: the moon will be below the horizon and the eclipse will unfold during daylight hours in North America.

New Moon, Harvest Moon & Partial Solar Eclipse — Sept. 21

The new moon falls on Sunday, Sept. 21, coinciding with a partial solar eclipse visible across portions of the southern Pacific. The Almanac notes that while the eclipse won’t be seen in North America, the date sets the stage for October’s Harvest Moon to take its turn as the closest full moon to the equinox.

Autumnal Equinox — Sept. 22

Autumn officially arrives on Monday, Sept. 22, 2025, at 12:19 p.m. MDT, when the sun crosses the celestial equator and day and night are nearly equal in length. For Summit County, the equinox marks the transition into longer nights, cooler air, and clearer skies—conditions ideal for stargazing.

Why Summit County Stargazers Should Look Up

Even without the eclipse, the Corn Moon on Sept. 7 will glow brightly over Utah skies, setting a luminous tone for the month. By the time the equinox arrives two weeks later, nights in the Wasatch Back will lengthen noticeably, offering darker, crisper evenings. For local stargazers, September provides the perfect moment to step outside, tilt their gaze skyward, and welcome the quiet clarity of autumn nights.