For many years, March 21st was regarded as the official start of spring. However, since 2012, the calendar spring has officially commenced on March 20. This year, spring will begin at 10:01 AM Central European Time (CET) on March 20, 2025. As we approach the middle of the 21st century, spring is increasingly beginning on March 19, with the next return to the traditional March 21 set to happen in 2102. This shift is due to the Earth’s inconsistent orbital period around the sun, which takes approximately 365 days, 5 hours, 48 minutes, and 46 seconds. To account for this discrepancy, leap years were implemented, but specific conditions, such as skipping a leap day at the start of centuries when not divisible by 400, create further irregularities.
The astronomical spring, defined by the equinox when day and night are equal, will officially commence this year on March 20. This date varies slightly each year, depending on the precise timing of the equinox, leading to potential start dates of March 19, 20, or 21. The differentiation between astronomical and meteorological spring is crucial, with the latter uniformly starting on March 1. This division aligns with standard meteorological practices, which divide the year into four distinct seasons based on three-month intervals for consistent weather data comparisons.
As nature transitions from winter to spring, the days are expected to lengthen, temperatures will rise, and flora and fauna will reawaken. This year's spring will last until June 21, 2025, a day known for the longest sunlight exposure in the northern hemisphere, marking the summer solstice.
The climate also plays a significant role in determining when spring begins. For allergy sufferers, the onset of spring often brings increased pollen levels as various plants begin to bloom. Notably, this year’s springtime will see the decline of hazel and alder pollen, while the birch blossoms will soon follow.
Despite the pleasure that longer days bring, particularly after winter’s chill, spring’s arrival can complicate life for many due to pollen allergies. Climate change continues to influence plant blooming schedules, resulting in extended exposure periods for those affected.
Looking back at the astronomical spring, until 1916, the season consistently commenced on March 21. The last occurrence of this date marking the astronomical start of spring was in 2011, and the next instance won’t be seen until 2102 when precisely calculated leap year rules shift the balance back to March 21.
The global perspective of spring illustrates even more fascinating variations. For astronomers, spring tends to start around March 20 based on the equinox, while meteorologists define spring to always begin on March 1. Moreover, biologists recognize a more intricate phasing of spring, correlating the seasons to plant life cycles, which may vary widely depending on geographic location.
The phenological calendar introduces another dimension to this seasonal transition. It recognizes an earlier spring characterized by developments in plant life, leading to three distinct phases: pre-spring, early spring, and full spring. The appearance of snowdrops and crocuses signifies the arrival of pre-spring, while violets and forsythias mark early spring. Full spring concludes with the blooming of apple trees and lilacs before transitioning into summer.
The timing of spring's arrival is complex, but one thing is certain: on March 20 at 10:01 AM, many parts of the Northern Hemisphere will welcome the season with warmer days and the promise of blooming life. With the changes in daylight hours—as the sun rises higher in the sky—there will be a perceptible shift for many with each passing day, eventually leading to the summer solstice.
As spring arrives, so do the adjustments in our clocks. In Germany, for instance, clocks will spring forward an hour on March 30, transitioning to Central European Summer Time. This yearly occurrence continues to prompt discussions, with many advocating for a standardized time throughout the year to benefit public health and productivity.
All in all, the arrival of spring is met with anticipation and excitement, but also thoughtful consideration of the environmental factors that shape our experiences with the seasons. Whether through changes in weather patterns, impacts on health, or the adjustment of formal definitions—this season represents a time of renewal and vibrant life.
