Scientifically, fall is a result of the Earth's tilt relative to the sun. As the planet orbits, the Northern Hemisphere begins to tilt away from the sun, resulting in shorter days and cooler temperatures. This reduction in sunlight triggers a biological response in the natural world. The most iconic symbol of the season is the changing of the leaves. As chlorophyll—the chemical that makes leaves green—breaks down due to lack of sunlight, the hidden pigments of yellow, orange, and red are revealed. This process transforms landscapes into tapestries of warm colors, creating a visual spectacle that signals the winding down of the year.
Of all the four seasons, fall—also known as autumn—occupies a unique space in the human imagination. It is a season of profound transformation, bridging the gap between the vibrant, energetic heat of summer and the silent, dormant cold of winter. While it is scientifically defined by the tilting of the Earth's axis and the shortening of days, fall is culturally and emotionally defined by its distinct atmosphere of change, reflection, and preparation.
The Earth’s tilt causes sunlight to become less direct. Days get shorter, temperatures drop, and the air feels crisp.
But fall is much more than a date on the calendar. It’s a season of dramatic change, color, and preparation.
Defined by the Earth's orbit and tilt, it begins at the autumnal equinox (roughly September 22 or 23 in the Northern Hemisphere) and ends at the winter solstice (December 21 or 22). On the equinox, day and night are nearly equal in length because the Sun is directly over the equator.
