Climate and Agriculture in the Southeast

Is this year’s frost earlier than usual?

Blairsville Experiment Station in far north-central Georgia had their first frost of fall 2015 on October 17, when it got down to 30.4 F, according to the UGA weather network at http://www.georgiaweather.net. Blairsville is one of the coldest parts of Georgia, and thus one of the first regions in the state to get frost.  I’ve gotten a few questions about whether this frost is earlier than usual.  You can check this for yourself using frost tables or graphs available from a number of places.  The graph below is from the cli-MATE system at the Midwestern Regional Climate Center (which requires a free account to log in) but there are similar graphs available at the Southeast Regional Climate Center and other places.  Here’s similar information from the SERCC in tabular form.The screen capture is not very clear so you might want to try it out for yourself.  The yellow curve for 32 F shows that in 70 percent of years, the first fall frost in Blairsville comes earlier than October 18, so by that standard it is actually a little later than usual (the middle is at 50% on October 10).

You can compare for the full period of record (Blairsville’s record goes from 1892 to the present) or for the last 30 years.  If you look at just the last 30 years, only 60% of first fall freezes came by 10/18, so the frost dates are somewhat later in the last three decades compared with the longer term pattern.  This is consistent with the rising temperatures we’ve generally seen in the Southeast since the 1970s.

Source: Midwestern Regional Climate Center

Source: Midwestern Regional Climate Center