Dog Days a Sirius business

July 3 is the first of the “Dog Days” of summer, but it doesn’t have anything to do with the hounds crawling under the porch in search of cooling shade.
The name comes from Sirius, the brightest visible star in the constellation Canis Major (Latin for Big Dog), and so Sirius has been called the Dog Star since ancient times.
The Greeks and Romans thought Sirius was at least partly responsible for summer’s heat, since it rose each morning about the same time as the sun, adding more heat during the hottest time of the year. They called the period dies carniculares, Dog Days.
Sirius is on a slightly different schedule now, but Dog Days traditionally ran from July 3, 20 days before the simultaneous appearance of the sun and star, to Aug. 11, 20 days after, and we still associate the name with the hot, lazy days of midsummer.
The ancients thought this was an evil time, when the seas boiled, wine turned sour, dogs went mad and “all creatures became languid, causing to man burning fevers, hysterics, and phrensies,” according to one old almanac.
Folks who have to work outdoors in the heat today might still share some of those opinions.
Indeed, July and August are generally our hottest days in Louisiana, when we quit saying, “it’s not the heat, it’s the humidity,” and start in with “it’s too doggone hot and too doggone humid, too.”
The 10 hottest months in south Louisiana on record, going back to the late 1800s, have all been in those two months. August 1951 has the distinction of being the hottest ever, when the average afternoon high was nearly 97 degrees and the overnight low was 74. The high for the day was 98 or higher on 11 of the 31 days that month.
Six of the top 10 hot months have been in July and four in August, and the highest temperature on record at Lafayette, 107 degrees, came on the afternoon of July 13, 1901.
Doctors have found that August, with its hot, humid, windless weather, is usually the most climatically stressful month of the year for people who live in south Louisiana. August temperatures are often as warm as the body’s temperature, or warmer. That means that people who work outside can’t depend on the air to cool them, and they have to rely on other means.
My preferred method is sitting in the shade of a big oak tree with a cooling beverage in hand, but that won’t get the grass mowed. There’s also some stress in worrying that August is also one of our busiest hurricane months. Shade won’t help that, but some cooling beverages might.
Over the long haul, our average afternoon high has been about 91.5 degrees in July and August; the average overnight low has been just over 72 in each of the two months.
But change is coming, if not for our stressful Augusts, at least for the poor Dog Star’s bad reputation. It has to do with our wobbly earth. LSU physics prof Bradley Schaefer explains that the earth can be compared to a top that wobbles as it spins. Just like the top, “the Earth’s rotation is kind of wobbling around,” and that causes the relative position of stars and planets in the sky to change about one degree every fifty years.
That means that in about 13,000 years, Sirius and the sun will rise together in the middle of winter, not in the middle of summer. July and August will still be hot, but the poor Dog Star won’t get the blame.

You can contact Jim Bradshaw at jimbradshaw4321@gmail.com or P.O. Box 1121, Washington LA 70589.