By - Drew Switzer
It was certainly chilly this morning with morning lows dropping into thte low to mid 40s. Hiawatha actually dropped all the way to 42 this morning. We have seen some snow showers flying out West. Summer is officially over. When will we see our first freeze? It does not appear we will drop below freezing anytime soon but our record low temperatures are now below freezing, so we have seen freezing temperatures before in late September, but that doesn not look to happen this year. '
In an average year, the first freeze in Topeka takes place between the 12th and 17th of October. The lastest Topeka has ever seen a freeze (temp at or below 32) is November 11th.
A frost is not always a freeze. You can frost on the ground when the official temperature only drops to 35 or 36 degrees. Remember, the official temperature is taken 6 feet off the ground. On calm ,clear night, we have what is called a low level inversion. Meaning, the temperature get warmer with hieght (it normally cools with height). So right at the surface you can have temperatures that actually make it to 32 degrees, cold enough for frost to form.
I want to define these terms for you. Definitions come from the National Weather Service.
A Frost typically requires an air temperature of less than 36 degrees, but also requires certain atmospheric moisture parameters in order to form. Frost can cause minor damage to some plants.
A Freeze occurs when the air temperature drops to 32 degrees or less. Sub-freezing temperatures may cause significant damage to plant life, particularly if temperatures remain below freezing for 3 or more hours.
A Hard Freeze occurs when the air temperature falls to 28 degrees or less. A hard freeze causes significant damage to plants, and essentially ends the growing season for almost all plant life.
I also want to attach a chart of the average freeze information.