Washington, D.C. — With summer winding down, Americans will soon notice a dramatic loss of daylight hours as the nation moves toward the autumn equinox. While days have been subtly shortening since the June 20 summer solstice, September will bring the most noticeable change.
According to AccuWeather meteorologists, many regions of the U.S. will see the fastest decline in daylight of the year during September, with some northern areas losing nearly 100 minutes of daylight. In Alaska, the drop will be even more severe — nearly 193 minutes of daylight gone in just one month.
Why We Lose Daylight in the Fall
The changing daylight hours are a direct result of the Earth’s axial tilt. During the planet’s orbit around the sun, there are two points — known as the equinoxes — when the Earth’s axis is tilted neither toward nor away from the sun.
The fall equinox occurs in September, and this year it will happen on September 22 at 2:19 p.m. ET. On that day, people along the Earth’s equator will see the sun directly overhead at noon.
The National Weather Service explained that the balance of day and night during the equinox is not exact:
“The ‘nearly’ equal hours of day and night is due to refraction of sunlight or a bending of the light’s rays that causes the sun to appear above the horizon when the actual position of the sun is below the horizon.”
This balance gradually shifts until the winter solstice in December, when the Northern Hemisphere experiences its shortest day and longest night.
How Much Daylight Will Be Lost in September?
By the end of September, Americans in most regions will see an hour or more of daylight disappear. Even in southern states, at least 40 minutes will be lost. Here’s how the daylight drop will look across several U.S. cities, according to USA TODAY:
- Miami, Florida: 43 minutes
- Austin, Texas: 52 minutes
- San Diego, California: 58 minutes
- Raleigh, North Carolina: 64 minutes
- New York City: 77 minutes
- Portland, Oregon: 91 minutes
- International Falls, Minnesota: 102 minutes
Cooler Air Will Follow
The shorter days will also bring fall-like weather patterns. AccuWeather Senior Meteorologist Isaac Longley noted that the sharp drop in daylight often leads to significant temperature swings.
“With such a large loss in daylight, fall-like weather can arrive quickly in September. This year will be no exception, with cool air spilling southward out of Canada and into the central and eastern U.S. through the first week or so,” Longley said.
Forecasters add that while cooler conditions will dominate early September in the Great Lakes, Northeast, Mid-Atlantic, and Ohio Valley, warm-ups are still possible later in the month.
“A return to summer-like weather is still possible across the northern tier of the country later in September,” Longley explained.
What to Expect
Labor Day weekend will already feel more like fall in some regions, with highs only in the 60s and 70s across the Northeast, Great Lakes, Mid-Atlantic, and Ohio Valley. Meteorologists say this shift is a clear signal that autumn weather is arriving on schedule.
What are your thoughts on shorter days and cooler evenings arriving so soon? Share your views in the comments below.
