Autumn Equinox 2025: Date, Time and Significance Explained

In some cultures, an equinox can signal the start of longer nights and cooler weather, while in others, it's a welcome sign of milder temperatures and more sunlight. Regardless of how they are viewed, the ability to observe and predict equinoxes is one of humanity's oldest astronomical skills.

What is an Equinox?

Twice a year, in March and September, an equinox occurs when the Earth's axis and orbit align. The Sun is positioned directly over the equator, giving both the Northern and Southern hemispheres an almost equal amount of daylight. The word "equinox" comes from the Latin words “aequus” (equal) and “nox” (night), reflecting the near-equal lengths of day and night experienced across the globe on these days.

March equinox: It marks the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere.

September equinox: It marks the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere.

When is the Autumn Equinox 2025?

As per NASA, this year, the autumn equinox will occur on 22 September 2025 at 19:19 BST (11:49 PM IST).

Earlier, the spring equinox took place on March 20, at exactly 09:01 UTC (or 2:31 PM IST). 

“However, that day/night length depends on where you are on Earth,” said NASA solar scientist Mitzi Adams. “For example, at the North and South Poles, the length of the day and night is six months!” Adams said.

Equinox Significance

Equinoxes mark a change of seasons across the globe. In March, the Northern Hemisphere welcomes warmer, longer days, while the Southern Hemisphere experiences shorter days and cooler nights. In September, this pattern reverses.

Around the world, equinoxes have also been tied to rituals and celebrations, symbolising balance, renewal, and connection between the universe and human beings. Each culture adds its own traditions and meanings to the arrival of spring or autumn, but the common theme remains one of transition and harmony.

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