To borrow from an old saying, "Spring has sprung, fall has fell, summer's here, and it's hotter'n" ... well, hotter'n spring.
To be a little more scientific about it, summer arrives in the northern hemisphere at 6:59 p.m. Central Daylight Time -- the moment of the June solstice. It's the longest day of the year in the northern hemisphere; most of the United States will see the Sun for about 14 to 16 hours.
Because of all that sunlight, temperatures are rising. But they haven't reached their peak.
One reason is that it takes a while to heat the ground, oceans, and atmosphere. They warm up slowly, but then they retain the heat pretty efficiently.
Another reason is that even though the days start getting shorter after the solstice, there are still more hours of daylight than darkness. As a result, we receive more solar energy than we lose. It's like filling a bathtub with the drain open -- as long as more water flows in than out, the tub gets fuller.
And finally, the Sun remains at a high angle in the sky throughout the summer, so more of its energy strikes us straight on -- like a flashlight aimed at your face instead of off at an angle.
So when you add this all up, we can expect that the days ahead will be hotter'n June.
But the few hours of darkness tonight offer up one skywatching treat: the Moon and the planet Jupiter. They rise in late evening. Jupiter looks like a brilliant star to the Moon's upper right.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.