Prepare for a spring that's about 30 seconds shorter than last year's, which was 30 seconds shorter than the one before. The changing length of the season is related to the tilt of the Earth's axis, LiveScience reports. It's a matter of what's known as precession, or the way the axis wobbles. The summer solstice occurs, as the Smithsonian explains, when the northern hemisphere is most tilted toward the sun. Precession changes exactly when that occurs, meaning it comes a little bit earlier each year.
The result is that we get a little more summer and a little less spring; this year, it's 93.65 days of summer and 92.76 of spring. Another factor in season length is the speed with which the Earth is traveling around the sun. Due to the elliptical shape of Earth's orbit, right now, we move fastest along that orbit between December and March, meaning winter and spring are shorter, while summer and autumn are longer. The shortening-spring trend won't last forever: Around the year 8680, the season will be at its shortest, at 88.5 days. After that, spring will start getting longer again. (A longer summer may mean a few more moody people are born.)