Annnnd we have our first sunburn report of the year! This burn occurred back on April 10th. So yes indeed, it’s certainly that “sneaky sunburn” time of year again, when the cooler air of April tricks you into forgetting just how strong the sun’s rays are getting!
As we continue to move through April, the sun will continue to climb higher in the sky. By higher, think of the angle measure above the southern horizon, when the sun is at the midpoint of its transit across the sky each day. Zero degrees would be flat to the southern horizon, while 90 degrees would be directly overhead. Here in The County, the sun’s highest point above the southern horizon ranges from only about 20 degrees around December 21st, to 68 degrees around June 21st.
While that 68-degrees-above-the-southern-horizon sun sure feels like it is directly overhead on a hot, still, late June or early July day, the fact is that no location in the Lower 48 ever has the sun directly overhead, not even the Florida Keys! The farthest north the sun, as seen from Earth, gets is 23.5 degrees north latitude. This is also known as the Tropic of Cancer. The latitude of Key West is 24.5 degrees north. If Key West were about 70 miles farther south, they would have the sun directly overhead on the summer solstice.
Back to “Sneaky sunburns,” by the end of this month, what I like to call the “solar intensity cousin” date will be around August 10th. This means that the sun’s intensity is the same on April 30th as it is on August 10th.
Everyone thinks of August 10th as a summer day, but they sure don’t think that about April 30th, yet it’s true, the sun’s “burn you” power is the same on those two dates! By the way, you can figure out any day’s “solar cousin” by simply counting the number of days, starting with the day you are on, right up to the Summer Solstice, June 21st. Then take that same number of days past June 21st and you will have your “solar cousin”, in terms of solar intensity.
By the way, as the sun is climbing in the sky and getting stronger, the Earth-Sun Distance is steadily increasing. In other words, the earth is moving away from the sun, even as its rays are getting more intense as we head toward our summer solstice. The reason? Earth’s orbit around the sun is elliptical, not circular, and, believe it or not, the sun is about 3 million miles farther from Earth in early July than it is in early January. Stated another way, near our climatologically warmest time of the year, the sun is 3 million miles father away than during our climatological coldest time of the year!
The main reason that it’s hot when it’s hot and not when it’s not, doesn’t have much to do with the Earth-Sun distance, it’s the tilt of Earth on its axis as it orbits the sun that is far more important. During our summer, we are tilted toward the sun, giving us our sun high-in-the-sky time of year, and during our winter, we are tilted away from the sun, giving us our sun low-in-the-sky-time-of-year.
Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.
