In the northern hemisphere, i.e. also in Slovakia, astronomical spring will occur on Friday, March 20, 2026, or vernal equinox. In Slovakia it will be at 3:47 p.m. Central European Time (CET), in the world at 2:47 p.m. Coordinated Universal Time (UTC). Last year, the vernal equinox also occurred on March 20, but at 10:01 a.m. CET. In the Southern Hemisphere, March 20, 2026 will be the first day of autumn.
At the moment of the equinox, the Earth in its orbit around the Sun finds itself at the point where the plane of the Earth’s equator passes through the geometric center of the solar disk. The sun’s rays thus fall perpendicularly to the earth’s axis, or directly to the equator, and illuminate the northern and southern hemispheres of the planet Earth equally.
Day and night will be approximately the same length across the globe. On this day, the sun shines above the horizon in all places of the globe for approximately 12 hours. The fact that day and night are the same length during the equinox gives rise to the Latin name of this phenomenon – aequinoctium, which means “same night”. In Bratislava, the sun rises at 05:54 and sets at approximately 18:04, which means that the length of the day is approximately 12 hours and 10 minutes.
The length of the day exceeds 12 hours, because after sunset, its rays are still visible for a while due to their refraction in the Earth’s atmosphere (refraction). From the moment of the vernal equinox, the days continue to lengthen, becoming longer than the night. It is valid until the summer solstice, which this year occurs on June 21 at 10:26 a.m. Central European Summer Time (CEST).
The lengthening of the days and also the fact that the sun rises higher above the horizon every day and its rays fall more directly on the earth’s surface, cause overheating of the atmosphere and gradual warming of the weather in the coming spring season.
The different length of day and night during the year and the alternation of seasons causes the Earth’s rotational axis to tilt by approximately 23.5 degrees. If the Earth’s axis were perpendicular to the Earth’s orbitthe days would be the same length throughout the year and the seasons would not change.
The vernal equinox does not occur at the same time every year. The reason is the different length of the astronomical and civil year. According to the calendar, a year lasts 365 days, but in reality the Earth orbits the Sun in 365 days, 5 hours and 48 minutes. To make up for this difference, one extra day is added every four years on February 29, changing the dates and times of the equinoxes.
The beginning of the astronomical spring varies between March 19 (this will happen in 2048) and March 21 (last time in 2011, next time in 2102), but it most often occurs on March 20, like this year.
