Seattle Gains 11 Extra Minutes of Daylight During Spring Equinox The spring equinox occurred at 7:46 a.m. PDT on Friday, marking the start of longer days for the northern hemisphere. While the idea that balancing an egg on its end is only possible during the equinox is a myth, the event does signal the beginning of the brightest six months of the year. The equinox happens twice annually when the sun’s rays strike the equator at a right angle, creating nearly equal periods of daylight and darkness. This occurs because Earth’s tilted axis causes the sun’s direct rays to cross the equator from south to north during the spring equinox, allowing the northern hemisphere to receive more sunlight for six months. The term “equinox” comes from Latin, meaning “equal night,” though in Seattle, the day is actually 12 minutes longer than 12 hours. This discrepancy arises due to atmospheric refraction, which bends sunlight and extends the visible daylight. A day with precisely 12 hours of daylight is called the equilux, which in Seattle coincided with St. Patrick’s Day. While the equinox itself doesn’t guarantee perfect day-night balance, it sets the stage for the gradual increase in daylight as spring progresses. As the season transitions, residents are encouraged to embrace the changing light and enjoy the extended hours of sunlight.#seattle #st_patrick_s_day #spring_equinox #equilux #atmospheric_refraction
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
