For many in India, the winter months bring a familiar chill, with weak sunlight and cold air. It might seem strange, then, to learn that our planet is actually at its closest point to the Sun during this very season. This astronomical fact feels counterintuitive, almost misleading, as January mornings offer no extra warmth from the slightly reduced cosmic gap.
The Annual Celestial Event Most Miss
Every year, without any fanfare, Earth reaches this point of closest approach, known as perihelion. Astronomers mark it on their calendars, but for most people, life goes on amidst the continuing cold. This apparent mismatch between distance and temperature has puzzled generations. The logical assumption that closeness equals warmth simply doesn't apply to our seasons. To understand why, one must shift focus from the Sun's distance to the angle at which its light strikes our planet.
When and What is Perihelion?
In early January each year, Earth's elliptical orbit brings it nearest to the Sun. Specifically, in early 2026, this event will occur around January 3. At perihelion, Earth is approximately 2.5 million kilometres closer to the Sun than it is in early July, when it is at its farthest point (aphelion). While this sounds like a vast distance in human terms, in the grand scale of space, it amounts to only about a 3% difference in the total Earth-Sun distance. This minor variation is insufficient to cause any noticeable change in our daily weather or the Sun's apparent brightness.
The Real Driver of Seasons: Earth's Tilt
According to NASA, the primary reason for the seasons is not our distance from the Sun, but the 23.4-degree axial tilt of our planet. As Earth journeys around the Sun, this fixed tilt alters how directly sunlight hits different hemispheres throughout the year.
When the Northern Hemisphere tilts toward the Sun, its rays strike more directly, and days are longer. This period is summer. Conversely, during January, the Northern Hemisphere tilts away from the Sun. Even though Earth is closer overall, sunlight arrives at a shallow angle, spreading its energy over a larger area and providing less effective heating. Days are shorter, and nights are longer, allowing more heat to escape. Simultaneously, the Southern Hemisphere enjoys summer with direct sunlight and longer days.
A Coincidence in Timing and Future Shifts
The fact that perihelion coincides with Northern Hemisphere winter is largely a coincidence that is not permanent. Over immense timescales, the gravitational pull from other planets, particularly Jupiter and Saturn, causes Earth's orbit to slowly rotate. This gradual shift means the date of perihelion creeps forward in the calendar. Thousands of years from now, it will occur in a different season.
While this shift will slightly alter the length of seasons—Northern Hemisphere summer is currently a few days longer than winter because Earth moves faster when closer to the Sun—the fundamental pattern of seasons driven by the axial tilt will remain unchanged.
Human intuition, built on earthly experiences like moving closer to a fire, struggles with the scales of space. The Sun is so immensely far that a small change in distance is negligible. The angle of exposure is everything. So, the winter sun feels weak not because it is farther, but because it shines on us at a low angle for shorter periods. And thus, January remains cold, even as our planet silently passes its closest solar point, a cosmic detail unnoticed by most going about their winter routines.
