ATLANTA -- Happy summer solstice! Wednesday is officially the first day of summer and the longest day of the year 2012. In fact, we will have just a little over 14 hours and 24 minutes of daylight. Compare that to the 9 hours and 5 minutes we have on the shortest day of the year at the end of December!
During the summer solstice, the sun reaches its northernmost point in the sky at local noon. That doesn't mean the sun was exactly overhead at noon for us. That only happens along the Tropic of Cancer, which is about where Cuba is.
This year's summer solstice takes place a day earlier than it's been for the past three years due to the fact that this year was a leap year. In general the exact timing of the summer solstice is around June 21, but changes from year to year ranging from June 20-22th.
The word solstice is derived from the Latin sol (sun) and sistere (to stand still), because during the solstice, the sun stands still during it's decline. Meaning, the annual movement of the sun (as seen from Earth) actually comes to a stop on the summer solstice before reversing direction. But it's all downhill from here, because starting Thursday, the days start getting shorter.
Earth's oceans and atmosphere act like heat sinks, absorbing and reradiating the sun's rays. Even though the planet is absorbing lots of sunlight on the summer solstice, it takes several weeks to release it. As a result, the hottest days of the year, don't actually occur until July or August.