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[EarthNSky <erthnsky AT bellsouth.net>]

While looking at some weather data, I came across this page that talks
about frosts and freezes and has some good information and advice about
planting locations to avoid damage.  I've pasted the guts of the article
here, but if you want to read more about frosts and freezes in GA, here
is the link
http://pubs.caes.uga.edu/caespubs/pubcd/MP117/MP117.htm

> 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
> 32o F) 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.


--
"The world is my country, all mankind are my
 brethren, and to do good is my religion."
 Thomas Paine (1737 - 1809)