Spring’s arrival brings seasonal changes and scientific significance

With spring right around the corner, the season has already made an early appearance this year with high temperatures, blooming flowers, pre-spring showers and later sunsets. But one lingering question remains: When is the first day of spring?

The answer depends on location. The March equinox will take place this Thursday at exactly 5:01 a.m. EST, marking the beginning of spring for those in the Northern Hemisphere. However, for those in the Southern Hemisphere, the March equinox signals the start of autumn. So for our friends down under in Australia, New Zealand, South Africa, Brazil, Argentina and parts of Indonesia and Africa, they’ll be gearing up for colder weather. Last year, the equinox occurred a day earlier on March 19 at 11:06 p.m. EST due to 2024 being a leap year. A typical calendar year consists of 365 days but Earth takes slightly longer to complete its orbit around the sun. According to NASA, the precise duration is approximately 365 days, 5 hours, 48 minutes and 46 seconds. The term “equinox” derives from the Latin words “aequus” (equal) and “nox” (night), referring to the nearly equal length of day and night that occurs during this event.

In nearly six months, the Northern Hemisphere will experience the autumnal equinox around Sept. 22 or 23, marking the transition into fall. During summer, the region undergoes the summer solstice, when Earth reaches its greatest axial tilt toward the sun, resulting in the longest day and shortest night of the year. During winter, the solstice occurs around Dec. 21 or 22, when Earth is tilted the farthest from the sun, making it the shortest day and longest night of the year in the Northern Hemisphere.

The concept of the spring equinox dates back to the 14th century, when ancient civilizations such as the Egyptians, Greeks and Persians associated the season with nature’s rebirth and fertility rituals. The equinox also plays a role in determining the date of Easter. The Council of Nicaea, convened by Roman Emperor Constantine, established Easter as the first Sunday after the full moon following the spring equinox, helping to standardize the holiday within the Christian Church. On March 20, 1896, the spring equinox was officially recognized as the first day of spring in the Northern Hemisphere.

An ancient equinox tradition, known as “the return of the sun serpent,” was created by the Mayans when they built the pyramid Kukulkan at Chichen Itza around A.D. 1000. During the spring equinox, the sun’s light casts shadows down the pyramid’s steps, creating the illusion of a snake slithering down.

During the equinox, day and night are nearly equal, with approximately 12 hours of daylight and 12 hours of nighttime. On March 20, the Northern Hemisphere will experience close to 12 hours of sunlight. After this point, the region will gradually tilt toward the sun, leading to longer daylight hours, brighter evenings and warmer weather.

However, determining the exact start of spring can be a bit complicated. Meteorologists recognize the start of spring as March 1, ending on May 31. Unlike astronomical calculations based on Earth’s position relative to the sun, meteorologists rely on temperature patterns, meaning early March’s increasing temperatures and seasonal showers are considered key indicators of spring in meteorology.

No matter how you choose to define spring’s arrival, its presence is here. Longer days, warmer temperatures and blooming landscapes signal a fresh start for many individuals. Whether viewed through an astronomical or meteorological lens, the season’s arrival marks a time of renewal and growth.