MP117 First and Last Frost Dates in Georgia

First and Last Frost Dates in Georgia

Joel O. Paz, Extension Agrometeorologist
and Gerrit Hoogenboom, Professor and REI Coordinator
Biological and Agricultural Engineering

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Frost Events
In many areas of Georgia, cold temperatures in late fall, winter and spring can pose a threat to row crops, fruit trees and horticultural plants. Exposure of sensitive crops to freezing temperatures (below 32^oF) can result in significant damage and, in some cases, total crop loss. For example, open peach and blueberry blooms are typically damaged at 28-29 ^oF and below, although green fruit may be damaged at higher temperatures. Susceptibility to frost depends on the health and growth stage of the plants, and the intensity and duration of the frost events.

The terms frost and freeze are often used synonymously, and frost events fall into two categories, namely: radiation and advective. Radiation frost is characterized by a clear sky, calm or very little wind, temperature inversion, a low dew point temperature and an air temperature that typically falls below 32° F during the night. Cooling occurs due to energy loss through radiant exchange during clear, calm nights (Snyder and Melo-Abreu, 2005). The temperature falls faster near the radiating surface, causing a temperature inversion, i.e., temperature increases with height above the ground. Radiation frost is the most common type of frost in Georgia. Advective frost occurs when a mass of cold air moves into an area and displaces warmer air that was present prior to the weather change. It is associated with cloudy conditions, moderate to strong winds, no temperature inversion and low humidity.

The potential for frost damage depends on local conditions. Both monitoring and local knowledge can prevent and/or minimize frost damage. Most farmers and growers have a good idea about areas of cold spots - where cold air settles - within their fields. As the air near the ground cools, it becomes denser and flows back down the slope. Generally, low spots where cold air settles are not suitable for planting frost-sensitive crops such as blueberries and peaches unless a frost protection system is installed. Also, areas where the natural or modified topography prevents cold air drainage from the site should be avoided. Because ground fog forms in low spots first, a good rule of thumb is to avoid places where ground fog forms early. Review local topographical maps before planting frost-sensitive crops on high-risk sites.

Frost affects different aspects of agricultural and horticultural production. There are more economic losses to frost damage than to any other weather-related phenomenon (White and Haas, 1975). Information about dates of the last frost events in the spring can help farmers decide when to plant their crops. Similarly, information on early frost dates in the fall can be useful for deciding when to harvest.

This extension circular is a compilation of first and last frost dates (Table 1) based on temperatures recorded at different weather stations of the Georgia Automated Environmental Monitoring Network (AEMN). The first frost event typically occurs in the fall. To determine this event, a computer program was used to search the weather records and identify the date between September 1 and December 31 when a particular station first recorded a temperature at or below 32^oF. For the last frost event, the program identified the last date between January 1 and May 31 when the temperature was at or below 32^oF.

The AEMN has more than 75 automated weather stations across Georgia (Figure 1). A list of the local site names are shown in Table 2. This circular will be updated every year as new stations are installed and additional data become available. Additional weather information can be found at www.georgiaweather.net.

Key Terms
Dewpoint temperature (or dewpoint): The temperature to which a given parcel of air must be cooled at constant pressure and constant water vapor content for saturation to occur.

Temperature inversion: A layer in which temperature increases with altitude. During daytime, the radiant energy of the sun warms the earth's surface. Air temperature decreases with height above the surface during the day. However, during nighttime, especially under clear skies, the earth’s surface, including plants and soil, radiates more heat to the sky than it receives, resulting in lower temperatures. Warmer air is now located above the cool air at the surface and this condition is referred to as a temperature inversion.

Figure 1. Map showing the location of the Georgia AEMN weather stations.

Table 1. First and last frost dates recorded at different stations.*
Station	Sept 1 to Dec 31	First Frost Date	Temperature °F	Jan 1 to May 31	Last Frost Date	Temperature °F

Alapaha	2007	7-Nov	28.8	2007	9-Apr	31.5
	2006	24-Oct	30.1	2006	27-Mar	29.7
	2005	26-Oct	30.2	2005	10-Mar	31.2
	2004	14-Dec	31.7	2004	23-Mar	30.4
	2003	29-Nov	27.9	N/A	N/A	N/A

Albany	2007	8-Nov	31.5	2007	19-Feb	25.6
	2006	5-Dec	26.9	2006	27-Mar	32.0
	2005	3-Dec	31.3	2005	4-Mar	31.4
	2004	15-Dec	26.0	N/A	N/A	N/A

Alma	2007	17-Nov	29.7	2007	8-Apr	28.9
	2006	5-Dec	28.4	2006	15-Feb	30.1
	2005	3-Dec	29.8	2005	2-Mar	30.7
	2004	14-Dec	31.2	2004	11-Mar	31.4
	2003	29-Nov	30.5	2003	12-Feb	31.8
	2002	23-Nov	29.9	2002	6-Mar	29.3
	2001	28-Oct	30.3	2001	6-Feb	31.3
	2000	21-Nov	27.8	2000	7-Feb	26.3
	1999	4-Nov	31.7	1999	25-Feb	30.0
	1998	18-Dec	26.2	1998	14-Mar	30.6
	1997	17-Nov	29.2	1997	12-Feb	28.7
	1996	10-Nov	31.9	1996	13-Mar	28.5
	1995	9-Nov	30.7	1995	9-Feb	17.1
	1994	24-Nov	30.0	1994	17-Mar	31.6
	1993	1-Nov	30.5	N/A	N/A	N/A

Alpharetta	2007	7-Nov	26.0	2007	9-Apr	31.2
	2006	23-Oct	31.9	2006	27-Mar	26.4
	2005	11-Nov	30.3	2005	19-Mar	29.8
	2004	15-Nov	31.6	2004	23-Mar	24.5
	2003	14-Nov	29.8	2003	1-Apr	31.0
	2002	14-Nov	30.0	N/A	N/A	N/A

Arabi	2007	8-Nov	26.6	2007	8-Apr	28.5
	2006	13-Nov	29.4	2006	27-Mar	30.7
	2005	N/A	N/A	N/A	N/A	N/A

Arlington	2007	7-Nov	31.4	2007	5-Mar	30.5
	2006	5-Dec	26.0	2006	27-Mar	31.3
	2005	18-Nov	29.4	2005	2-Mar	30.1
	2004	14-Dec	31.2	2004	19-Feb	30.1
	2003	14-Nov	31.3	2003	28-Jan	24.3
	2002	23-Nov	30.3	2002	23-Mar	29.0
	2001	28-Oct	29.9	2001	8-Mar	30.4
	2000	21-Nov	27.3	2000	9-Apr	31.9
	1999	4-Nov	29.7	1999	5-Mar	30.2
	1998	16-Dec	31.5	1998	14-Mar	31.9
	1997	17-Nov	24.9	1997	16-Feb	30.3
	1996	19-Dec	20.1	N/A	N/A	N/A

Atlanta	2007	16-Nov	30.9	2007	8-Apr	29.2
	2006	21-Nov	30.3	2006	26-Mar	31.3
	2005	17-Nov	31.2	2005	9-Mar	31.6
	2004	14-Dec	27.5	2004	26-Feb	31.3
	2003	25-Nov	27.6	2003	31-Mar	30.7
	2002	18-Nov	30.3	2002	23-Mar	26.9
	2001	25-Dec	27.4	2001	27-Mar	30.9
	2000	18-Nov	29.6	2000	6-Feb	28.2
	1999	1-Dec	31.4	1999	12-Mar	30.7
	1998	18-Dec	30.8	1998	28-Apr	32.0
	1997	16-Nov	29.0	1997	16-Mar	31.8
	1996	3-Nov	31.2	1996	22-Mar	28.7
	1995	9-Nov	30.4	N/A	N/A	N/A

Attapulgus	2007	8-Nov	29.1	2007	5-Mar	31.5
	2006	5-Dec	27.8	2006	27-Mar	30.5
	2005	23-Nov	30.9	2005	4-Mar	32.0
	2004	15-Dec	25.4	2004	11-Mar	31.7
	2003	25-Nov	31.2	2003	2-Feb	31.9
	2002	23-Nov	30.9	2002	9-Apr	32.0
	2001	26-Dec	26.4	2001	7-Feb	30.2
	2000	21-Nov	27.9	2000	13-Mar	30.1
	1999	4-Nov	30.8	1999	5-Mar	29.3
	1998	16-Dec	31.0	1998	14-Mar	29.3
	1997	17-Nov	28.4	1997	12-Feb	26.0
	1996	10-Nov	31.2	1996	23-Mar	24.7
	1995	22-Oct	31.2	1995	2-Apr	30.8
	1994	24-Nov	29.3	1994	14-Feb	30.8
	1993	31-Oct	31.6	1993	15-Mar	25.8
	1992	1-Sep	32.0	N/A	N/A	N/A

Baxley	2007	7-Nov	30.2	N/A	N/A	N/A

Blairsville	2007	30-Oct	26.9	2007	19-May	32.0
	2006	13-Oct	28.8	2006	10-Apr	30.8
	2005	26-Oct	30.9	2005	4-May	30.3
	2004	6-Nov	27.3	2004	5-May	29.8
	2003	16-Oct	30.3	2003	31-Mar	26.3
	2002	18-Oct	31.2	2002	21-May	31.4
	2001	26-Sep	31.9	2001	27-Apr	30.5
	2000	8-Oct	26.0	2000	28-Apr	28.1
	1999	23-Sep	30.3	1999	1-May	31.3
	1998	22-Oct	29.5	1998	24-Apr	30.6
	1997	22-Oct	29.9	1997	17-May	29.7
	1996	10-Oct	31.4	1996	1-May	29.0
	1995	17-Oct	29.8	1995	3-May	30.9
	1994	18-Oct	31.6	1994	8-Apr	25.5
	1993	4-Oct	30.5	1993	29-Apr	31.9
	1992	12-Oct	31.2	1992	30-Apr	27.5

Blue Ridge	2007	30-Oct	29.0	2007	10-Apr	26.7
	2006	13-Oct	30.9	N/A	N/A	N/A

Brunswick	2007	17-Dec	31.4	2007	19-Feb	30.1
	2006	8-Dec	31.1	2006	14-Feb	30.7
	2005	22-Dec	31.0	2005	2-Mar	32.0
	2004	15-Dec	29.8	2004	8-Feb	31.0
	2003	30-Nov	30.4	2003	28-Jan	29.8
	2002	29-Nov	31.4	2002	26-Mar	32.0
	2001	27-Dec	29.4	2001	26-Jan	29.4
	2000	22-Nov	27.2	2000	6-Feb	27.8
	1999	2-Dec	29.6	N/A	N/A	N/A

Byromville	2007	7-Nov	31.4	2007	8-Apr	28.8
	2006	13-Nov	31.8	2006	26-Mar	29.7
	2005	18-Nov	30.2	N/A	N/A	N/A

Byron	2007	8-Nov	29.5	2007	8-Apr	28.3
	2006	4-Nov	31.9	2006	26-Mar	31.0
	2005	18-Nov	28.1	2005	9-Mar	29.7
	2004	26-Nov	31.8	2004	23-Mar	30.3
	2003	25-Nov	29.0	2003	31-Mar	31.4
	2002	18-Nov	29.6	2002	23-Mar	29.2
	2001	28-Oct	30.1	2001	8-Mar	30.3
	2000	20-Nov	31.6	N/A	N/A	N/A

Station	Sept 1 to Dec 31	First Frost Date	Temperature °F	Jan 1 to May 31	Last Frost Date	Temperature °F

Cairo	2007	8-Nov	30.9	2007	5-Mar	31.5
	2006	5-Dec	26.3	2006	27-Feb	30.6
	2005	23-Nov	32.0	2005	2-Mar	29.6
	2004	14-Dec	31.8	2004	19-Feb	31.0
	2003	25-Nov	31.0	2003	28-Jan	27.1
	2002	23-Nov	29.8	2002	6-Mar	28.8
	2001	21-Dec	29.6	2001	8-Mar	31.5
	2000	21-Nov	26.9	2000	10-Apr	31.5
	1999	25-Oct	30.6	1999	28-Mar	32.0
	1998	7-Nov	31.6	1998	14-Mar	27.6
	1997	16-Oct	N/A	N/A	N/A	N/A

Calhoun	2007	30-Oct	27.6	2007	16-Apr	28.8
	2006	14-Oct	28.6	2006	5-Apr	31.3
	2005	26-Oct	31.3	2005	25-Apr	28.9
	2004	6-Nov	30.6	2004	6-Apr	30.1
	2003	24-Nov	31.9	2003	1-Apr	30.5
	2002	8-Nov	31.0	2002	6-Apr	31.2
	2001	17-Oct	31.2	2001	19-Apr	28.5
	2000	10-Oct	28.6	2000	10-Apr	31.1
	1999	25-Oct	26.8	1999	28-Mar	28.2
	1998	23-Oct	23.8	1998	12-Apr	28.0
	1997	23-Oct	31.1	1997	15-Apr	31.7
	1996	19-Oct	31.8	1996	11-Apr	28.9
	1995	4-Nov	29.7	1995	12-Mar	30.4
	1994	24-Nov	30.2	1994	13-Mar	31.0
	1993	1-Nov	26.6	1993	23-Apr	31.8
	1992	20-Oct	31.7	1992	3-Apr	24.

Camilla	2007	8-Nov	28.5	2007	5-Mar	30.6
	2006	4-Dec	31.8	2006	27-Mar	30.0
	2005	18-Nov	31.5	2005	2-Mar	27.7
	2004	14-Dec	30.6	2004	11-Mar	31.6
	2003	25-Nov	28.6	2003	12-Feb	31.3
	2002	23-Nov	30.5	2002	23-Mar	31.6
	2001	29-Oct	31.6	2001	8-Mar	30.9
	2000	15-Nov	31.9	2000	10-Feb	30.4
	1999	4-Nov	29.7	1999	5-Mar	31.8
	1998	16-Dec	30.5	1998	13-Mar	28.6
	1997	17-Nov	27.0	N/A	N/A	N/A

Clarks Hill	2007	7-Nov	28.9	2007	10-Apr	31.9
	2006	25-Oct	30.4	2006	27-Mar	28.0
	2005	12-Nov	31.1	2005	19-Mar	30.7
	2004	15-Nov	29.0	N/A	N/A	N/A

Cordele	2007	8-Nov	28.1	2007	19-Feb	25.3
	2006	4-Nov	31.2	2006	27-Feb	29.0
	2005	18-Nov	28.0	2005	4-Mar	29.9
	2004	16-Nov	31.0	2004	23-Mar	29.2
	2003	25-Nov	29.2	2003	13-Feb	31.4
	2002	18-Nov	31.7	2002	23-Mar	31.0
	2001	28-Oct	29.9	2001	8-Mar	32.0
	2000	22-Nov	24.5	2000	10-Feb	31.7
	1999	4-Nov	30.5	1999	5-Mar	31.4
	1998	18-Dec	25.6	1998	13-Mar	28.3
	1997	17-Nov	28.2	N/A	N/A	N/A

Covington	2007	30-Oct	30.0	2007	10-Apr	31.8
	2006	24-Oct	30.7	2006	26-Mar	29.0
	2005	11-Nov	31.5	2005	19-Mar	30.9
	2004	16-Nov	29.2	2004	23-Mar	30.5
	2003	14-Nov	31.6	2003	1-Apr	31.6
	2002	14-Nov	31.3	N/A	N/A	N/A

Dahlonega	2007	7-Nov	26.1	2007	10-Apr	28.3
	2006	14-Oct	31.6	2006	27-Mar	24.8
	2005	26-Oct	30.4	2005	19-Mar	28.5
	2004	15-Nov	27.4	2004	4-May	31.5
	2003	14-Nov	28.1	2003	1-Apr	30.8
	2002	8-Nov	30.6	N/A	N/A	N/A

Dallas	2007	7-Nov	29.3	2007	9-Apr	31.6
	2006	25-Oct	30.8	2006	27-Mar	27.4
	2005	29-Oct	31.9	2005	24-Apr	32.0
	2004	15-Nov