On average, spring lasts approximately 92.8 days in the Northern Hemisphere and 89.8 days in the Southern Hemisphere. The exact duration can vary slightly year to year.
Understanding Spring's Duration
The Earth's orbit around the Sun is not a perfect circle; it's an elliptical (oval) path. Due to this elliptical orbit, the Earth's speed as it travels around the Sun is not constant. It moves faster when it's closer to the Sun and slower when it's farther away. This variation in orbital speed is the primary reason why the seasons, including spring, are not of equal length.
Spring's Average Length by Hemisphere
The duration of spring differs between the Northern and Southern Hemispheres because their spring seasons occur at opposite times of the year, corresponding to different points in Earth's elliptical orbit.
Here's an overview of the average duration of spring:
Hemisphere | Average Duration |
---|---|
Northern Hemisphere | 92.8 days |
Southern Hemisphere | 89.8 days |
What Influences Spring's Length?
The varying length of spring and other seasons is directly linked to celestial mechanics:
- Earth's Elliptical Orbit: As mentioned, the Earth's path around the Sun is not perfectly circular. This means the distance between the Earth and the Sun changes throughout the year.
- Varying Orbital Speed: When Earth is closer to the Sun (perihelion, around early January), it moves faster. When it's farther away (aphelion, around early July), it moves slower. Seasons that occur when Earth is moving slower will consequently last longer. For instance, the Northern Hemisphere's summer and spring occur when Earth is moving slower relative to its winter and autumn.
For more information on the start and length of seasons, you can refer to resources like Time and Date.