CHARLESTON, W.Va. — Fall has already been underway for three weeks in West Virginia. On Tuesday evening, it begins again.
The apparent contradiction stems from two different ways of measuring the seasons. Meteorological fall began Sept. 1, while astronomical autumn begins with the September equinox, which arrives at 8:05 p.m. Tuesday.
In a mountainous state such as West Virginia, however, neither date necessarily reflects what people see outside their windows.
Autumn does not arrive everywhere here at once. It works its way across a landscape that rises from relatively low river valleys to mountains more than 4,000 feet above sea level, producing differences in temperature, vegetation, and the timing of seasonal change.
Why does fall begin twice?
Meteorologists divide the year into four three-month seasons based on the annual temperature cycle. Fall therefore includes September, October, and November and always begins Sept. 1.
Astronomical seasons are determined by Earth’s position in relation to the sun. The September equinox occurs when the sun crosses the celestial equator from north to south. In 2026, that happens Tuesday evening in West Virginia.
The distinction is useful for scientists. Fixed three-month periods make it easier to compare temperatures and other weather records from year to year, while the astronomical calendar follows Earth’s changing relationship with the sun.
For someone watching the mountains of West Virginia, however, a third calendar matters: what is actually happening outdoors.
In West Virginia, autumn moves downhill
Elevation makes West Virginia’s seasonal transition especially conspicuous.
Nowhere is the difference more apparent than in the Allegheny Mountains of eastern West Virginia. The Monongahela National Forest alone ranges from about 1,000 feet above sea level to 4,863 feet at Spruce Knob, the state’s highest point.
That vertical landscape helps stretch autumn across weeks rather than days. West Virginia tourism officials advise fall travelers that higher elevations change color first, with the progression generally moving into lower elevations as the season advances.
Travelers can therefore encounter noticeably different stages of autumn within the same state. A high-mountain landscape may already appear distinctly autumnal while valleys farther down remain largely green. Later, leaves may be past peak in the highest mountains while lower elevations are approaching their brightest color.
The result is a fall season that unfolds across West Virginia rather than arriving everywhere on a single date.
The equinox doesn’t mean day and night are exactly equal
The word “equinox” comes from Latin for “equal night,” but Tuesday will not yield exactly 12 hours of daylight and 12 hours of darkness.
The equinox is an astronomical instant rather than an all-day event. It occurs when the sun crosses the celestial equator.
Earth’s atmosphere also bends sunlight near the horizon, keeping the sun visible slightly before its geometric sunrise and after its geometric sunset. As a result, daylight around an equinox is slightly longer than 12 hours in many places.
So when does fall really begin?
All three answers can be correct, depending on what someone means by “fall.”
For meteorologists, autumn begins Sept. 1. For astronomers, autumn begins Tuesday evening. For someone standing on a West Virginia mountainside, the answer may be visible in the forest.
The state’s varied elevations mean autumn behaves less like a date on a calendar than like a progression across the landscape. Higher mountains may be moving into fall while the lower country still looks much like summer. Weeks later, the high country may be past peak color while the valleys are only reaching their brightest stage.
Tuesday’s equinox therefore does not suddenly bring autumn to West Virginia. It marks a moment in a seasonal change already underway in the mountains and one that still has a long way to travel.