Introduction to the Autumnal Equinox
While many people mourn summer with the passing of Labor Day Weekend, the autumnal equinox is the official end of the summer season. Besides sweater weather and pumpkin-spiced menu items, what does the equinox mean, and when is it in 2025?
What is the Autumnal Equinox?
The autumnal equinox marks the start of autumn in the Northern Hemisphere. The Earth travels around the sun at an angle, and for most of the year, the Earth’s axis is tilted either toward or away from the sun. That means the sun’s warmth and light fall unequally on the northern and southern halves of the planet. When the Northern Hemisphere is tilted toward the sun, that’s called the summer solstice. This marks the first day of summer in the North and the first day of winter in the South. 180 days later, when the Southern Hemisphere is tilted toward the sun, it is called the winter solstice. This marks the first day of winter in the North and the first day of summer in the South.
The halfway points between these solstices are the autumnal and vernal equinoxes. The word equinox comes from two Latin words meaning equal and night. That’s because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet. This provides approximately 12 hours of day, followed by 12 hours of night.
When is the 2025 Autumnal Equinox?
This year, the autumnal equinox in the Northern Hemisphere — which can land between Sept. 21 and 24 depending on the year — will occur on Monday, Sept. 22 at 2:19 p.m. EST / 11:19 a.m. PT. This year, there’s a bonus for some: Antarctica, New Zealand and a sliver of Australia may be able to see a partial lunar eclipse during their Monday.
Difference Between Meteorological and Astronomical Seasons
These are two different ways to carve up the year. While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. Meteorologists break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1.
The Harvest Moon
The "Harvest Moon," which refers to the full moon that occurs closest to the autumnal equinox, is still a ways away. The name dates back to a time before electricity when farmers depended on the moon’s light to harvest their crops late into the evening, according to NASA. This year, due to the lunar cycle, the harvest moon falls on Oct. 6. While it is visually no different than any other full moon, the fall moon has inspired songs, poems and stories throughout history.
Conclusion
Mark your calendar because the seasons are changing! The autumnal equinox is a significant event that marks the beginning of autumn in the Northern Hemisphere. Understanding the difference between astronomical and meteorological seasons can help you appreciate the changing seasons. The harvest moon, which occurs closest to the autumnal equinox, is a beautiful sight to behold and has inspired many works of art throughout history.
FAQs
- Q: When is the autumnal equinox in 2025?
A: The autumnal equinox in the Northern Hemisphere will occur on Monday, Sept. 22 at 2:19 p.m. EST / 11:19 a.m. PT. - Q: What is the difference between astronomical and meteorological seasons?
A: Astronomical seasons depend on how the Earth moves around the sun, while meteorological seasons are defined by the weather. - Q: When is the harvest moon in 2025?
A: The harvest moon falls on Oct. 6, 2025. - Q: What is the significance of the autumnal equinox?
A: The autumnal equinox marks the beginning of autumn in the Northern Hemisphere and is a significant event in the changing of the seasons.
