DENVER -- G’day, mate! Throw another shrimp on the barbie and let’s celebrate fall!

For our neighbors in the Southern Hemisphere, shorter days, longer nights, and generally cooler weather are in store for Kiwis and Aussies alike for the next several months as the planet heads toward the Winter Solstice in June.

Autumn is now underway in the land down under, as the Earth crossed the celestial equator at 5:44 a.m. MDT.

For those of us located in northern climes, spring just sprang forth.

Winter is over. Not that you'll notice much of a difference, since snow has been a rarity this season.

Our recent run of 70 degree temperatures has me reminiscing about March 2003 and big snow.

So, what just happened?

Whether you are soaking up the sunrays on the beaches of Australia, or carving the slopes in the Colorado Rockies, the Earth was busy crossing directly over the equator this morning on its way toward the solstice. It's the Vernal Equinox, or the Autumnal Equinox, if you are busy grilling on the barbie down under.

The beginning of spring and fall are the only two times of the year when the Sun rises due east and sets due west over the equator.

The Sun's position over the equator means that day and night are approximately equal, though the reality of that occurrence really depends on where you are located on this Pale Blue Dot. In other words, latitude counts.

The reason for the season is simple. The Earth's 23.5 degree tilt makes it all possible, and it is why we get the seasons that we do.

Because of the tilt, the Sun's rays are more intense during the summer months when the Earth's axis tilts toward our star. The opposite is true during the winter, when the Earth's axis tilts away from the Sun.

All things being equal, spring and fall receive comparable sunlight, and the weather of each season is similar.

The beginnings of these seasons are the equinoxes, after all.