For those who are caught in the throes of winter, it’s hard to believe, but it’s true – Earth is snuggling closest to the Sun for the entire year this week. We’ll be at our absolute closest tomorrow, at about 91 and a half million miles – about a million and a half miles closer than average.

That change in distance doesn’t make much difference in the temperature – Earth’s oceans and atmosphere do a good job of distributing heat around the globe.

Instead, the seasons are caused by Earth’s tilt on its axis. At this time of year, the south pole tips toward the Sun, so the southern hemisphere sees longer days. That means there’s more sunlight to warm things up. And the Sun climbs higher in the sky, so its rays fall most directly on the southern hemisphere, making it warmer still.

It’s the reverse of that north of the equator. The north pole tilts away from the Sun, so the days are short and the Sun stays low in the sky.

And the farther north you go, the lower the Sun appears. Just north of the Arctic Circle, in fact, there’s no sunlight at all. Most of the United States sees about 9 or 10 hours of sunlight. But the Sun’s at such a low angle that it doesn’t warm things up much.

That will change over the coming months, though. The Sun is moving slowly northward, so it’ll climb higher in northern skies, and stay in view longer. It’ll peak in a bit less than six months – when Earth is farthest from the Sun.

Script by Damond Benningfield