Fall is here which means the days are getting shorter and the nights are getting longer.
The decreasing sun angle means it’s lower in the sky leading to crisp fall nights and pleasant autumn days. This also means the days of the growing season are numbered and the National Weather Service has instituted the Fall Frost/Freeze Program of 2016 as a result.
According to the Farmer’s Almanac, the average first frost in Columbus is October 13. But the average first freeze (32 degrees Fahrenheit or lower) in Columbus is October 27, per the NWS. There’s a difference in the numbers are due to the fact that the temperatures are taken five feet above the ground. Because of that, the sensor may read 36 while it cools down to freezing at the surface where the winds are lighter and temps can drop a little further. That also means when the temperature reads 32 it may actually be even cooler at the surface.
Columbus has hit 32 as early as September 21st.
As we move through the season you may see Frost Advisories or Freeze Watches/Warnings.
So what’s the difference between the different classifications?
A Frost Advisory is issued when the low is forecast to drop between 33 and 36 degrees on a clear and calm night during the growing season.
A Freeze Watch is issued when we have the potential for a widespread freeze within the next 24-36 hours. A Freeze Warning is issued when a widespread freeze is in the forecast. These are issued in autumn until the end of the growing season by the NWS. The growing season ends once the first widespread freeze hits.
You may also be familiar with the term “Hard Freeze”. This occurs when temperatures drop to 28 or below which is enough to kill most vegetation. While there’s no temporal requirement to make it a hard freeze in this area it usually means we hit 28 or below for three to four hours.
The NWS will officially end the Frost/Freeze Program by November 7 in Columbus, regardless of whether or not we see our first freeze of the season.
