September 1 the start of Meteorological Fall

Eleven degrees, that’s how far Columbia’s monthly temperature falls throughout the entire month of September. On September 1st each year, Columbia typically sees an average of high of 84 degrees and closes out the month with a high of 73.

It’s a sign that fall and winter are just around the corner and that mid-Missourians will soon catch a break from the heat.

Here in the Northern Hemisphere Meteorological Fall is defined as the months September, October, and November. But, how does it differ to Astonomical Fall that starts on September 22nd?

In short, meteorological seasons are based on the annual temperature cycle of the earth and are grouped by months to make record-keeping easier. Astronomical seasons, however, are based on the position of the earth in relation to the sun.

For us here in the Northern Hemisphere, we’ll continue to see significantly cooler temperatures for at least the next six months.

This brings about the return of snow and subfreezing temperatures to a good portion of the country. Those in the Southern Hemisphere are seeing just the opposite in temperatures. They’re now heading into the warmer months, with summer right around the corner.

The difference between the two hemispheres as far as climate is all thanks to the tilt of the earth and where the direct rays of the sun set up. Here in mid-Missouri we are beginning to tilt away from the sun, which means chillier mornings.

Some statistics on fall averages for Columbia through the end of November show the drastic change in temperatures that you can expect to see during the cooler months. The average high drops from 84 degrees in September to 53 degrees in November, with overnight lows dipping down to 35 degrees. Before you know it, we’ll start to see those morning lows dip into the 30s, but don’t think of snow just yet. Historically speaking, the first average snowfall will hold off until at least the first week of December.