For many folks around here, summer began on Memorial Day weekend. To a lot of meteorologists, June 1 is the start of summer. But officially, summer arrives in just about 4 hours, at 9:48pm Eastern Daylight Time.

At that time, the earth will be at a point in its orbit that allows the sun to be directly overhead as far north on earth as it ever gets - 23 and a half degrees north of the equator, the so-called Tropic of Cancer. This latitude circle passes just south of the southern tip of Florida - through approximately Havana, Cuba - and passes just north of Hawaii.

The sun is highest in the sky around noon. To determine where the sun will be directly overhead at 9:48 this evening our time, we need to go about 10 times zones west of here. That puts us in the far western Pacific Ocean, south of Japan. This evening, when it's 9:48 here, the sun will be right overhead there. A person standing at that point will cast no shadow, and we can finally toast to the official start of summer.