SOUTH MISSISSIPPI (WLOX) - Wednesday is the first day of Autumn! Get ready to say bye-bye to hotter weather and hello to shorter days. Here are some facts about the local fall season.
Around late September marks the time of year when the Mississippi Gulf Coast typically sees its final 90°+ day of the year.
In Biloxi, the earliest final 90°+ day was Aug 29 (1957); the latest was Oct 28 (1963). These records date back to the late 1800s.
Biloxi's most recent 90° day was on September 20th as of this writing. Could that be 2015's final 90° day here?
Well, it's too early to tell until we get to about mid-October. However, the forecast calls for temperatures to remain below 90° pretty much through the end of September. So, unless we see a heat wave in October, we may not see 90° again until 2016!
The shortening of days contributes to the cooler temperatures seen during fall and winter. Each day is still 24 hours long. But, there is less daylight each day.
For us folks in the northern hemisphere, the darker days actually began in late June, on the summer solstice. Since then, we've been losing a few minutes of daylight each day as the sunrise gets later and the sunset gets earlier.
The autumnal equinox occurred earlier Wednesday morning, marking the official beginning of fall. An equinox happens twice a year: in spring and in fall. What's an equinox? The equinox is defined as when the earth's axis is tilted neither toward nor away from the sun, resulting in nearly equal amounts of daylight and darkness.
Even though the word 'equinox' literally means "equal day and night," there's actually a different day that signifies when the day and night are equal in length. That day is called the equilux. In Biloxi, the equilux occurs four days after the fall equinox: we'll be as close as possible to exactly 12 hours of daylight on Sunday, September 27th (sunrise: 6:47am, sunset: 6:46pm).
By October's end, Biloxi will only have 11 hours of daylight. And we'll finally reach our shortest day of the year (around 10 hrs, 11 mins of daylight) around the end of December when the winter solstice occurs.