Spring Equinox Marks the Start of Astronomical Spring The spring equinox is approaching and signals the beginning of astronomical spring in the northern hemisphere. This year, the event will occur on 20 March at 14:45, marking the moment when the Earth’s axis is tilted neither toward nor away from the Sun. This alignment results in nearly equal daylight and darkness across the globe, though the exact timing of equal day and night varies slightly due to atmospheric refraction. The equinox happens twice annually, once in March and once in September, and is determined by the Earth’s axial tilt of 23.5 degrees. As the planet orbits the Sun, this tilt shifts, leading to seasonal changes. During the equinox, sunlight is distributed equally between the northern and southern hemispheres. For regions south of the equator, the event heralds the start of autumn. The term "equinox" originates from Latin, combining "equi" (equal) and "nox" (night). While the equinox is often associated with equal day and night, this is not entirely accurate. In the UK, the actual day when daylight and darkness are precisely balanced occurs a few days earlier, on 18 March, known as the equilux. This discrepancy arises because the Sun’s position is measured from its center, and atmospheric refraction extends daylight beyond the moment the Sun disappears below the horizon. Astronomical spring officially begins on the equinox, whereas meteorological spring, used by weather forecasters, starts on 1 March. This distinction allows for more consistent annual comparisons of weather patterns. The months of March, April, and May are considered spring in the meteorological calendar, but the equinox marks the start of the astronomical season.#spring_equinox #earth_axis #sunlight_distribution #equilux #meteorological_spring
