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The winter solstice is here today (Dec. 21), marking the shortest day and longest night of the year for the Northern Hemisphere.

As the astronomical start of winter, today is the moment the sun reaches its lowest point in the sky as seen from Earth. At noon, it appears directly over the Tropic of Capricorn, a latitude of 23.5 degrees south, creating the least daylight of the year for the Northern Hemisphere, which is tilted as far from the sun as it gets.

This turning point lasts only an instant. The exact moment of the 2025 winter solstice occurs today at 10:03 a.m. EST (1503 GMT), officially ushering in the new season.

With the sun tracking low across the horizon, its rays arrive at a shallow angle, spreading light over a larger area and reducing heating. It's this lower solar angle, not our distance from the sun, that drives the coldest months of the year. But from this point forward, daylight will slowly begin to increase as we begin the slow march toward spring.

Earth's seasons exist because our planet is tilted by 23.5 degrees on its axis. As Earth orbits the sun, different hemispheres lean toward or away from it, changing the intensity and duration of sunlight. When the Northern Hemisphere tilts toward the sun, we get summer; when it tilts away — as it does now — we have winter.

Meanwhile, the Southern Hemisphere is experiencing its summer solstice today, enjoying the longest day of the year.

Although many assume winter corresponds to Earth being farther from the sun, the opposite is true. Earth actually reaches perihelion, its closest point to the sun, early next month on Jan. 3, 2026. At that moment, our planet will sit about 91.4 million miles (147.1 million kilometers) from the sun, slightly closer than its average distance of 93 million miles (149.6 million km).

Many cultures mark the winter solstice as a moment of renewal and the symbolic return of light. Starting tomorrow, daylight begins to grow again, a reminder that brighter, warmer days are on the way.