First Freeze Climatology of the Arklatex

The Arklatex region has a fairly extended growing season… the end of which is typically marked by what is referred to as the first freeze of the year. A freeze is simply defined as overnight low temperatures falling to 32 degrees or lower. The city of Shreveport averages 39 freezes a year…with rural and/or northern locations of the Arklatex averaging quite a few more. On average…the first freeze of the year occurs across hilly portions of southeast Oklahoma and southwest Arkansas around late October…while the first freeze across central portions of Louisiana do not occur until the second week of November. Larger cities tend to hold in slightly more heat overnight than do neighboring rural areas…thus the average first freeze in Shreveport is more in line with that of central… rather than northwest Louisiana. However…freeze warnings are only issued by The National Weather Service when a freeze is expected to have some kind of Impact. Thus…freeze warnings are typically limited to the first freeze of the season…a freeze after an extended period of warmth…such as a late autumn "Indian summer"…or during a spring freeze…after flowers and plants have begun to bud. Freeze warnings are also issued during a hard freeze… defined as temperatures falling below 15 degrees F generally across southeast Oklahoma…and portions of northeast Texas and southwest Arkansas…along and north of interstate 30. Across remaining portions of the area the threshold for a hard freeze is 20 degrees F. Hard freezes normally occur infrequently…with some entire winter seasons not experiencing a single one.

Some confusion can exist regarding the difference between a freeze and a frost. Although the two frequently occur together… they are not one and the same. Frost…which forms as a direct change of phase from water vapor to ice crystal…occurs during good radiative cooling conditions…when the sky is clear and winds are near calm. The actual air temperature can possibly be a few degrees above freezing…although typically below 40 degrees F. However…the surface temperature of objects affected such as blades of grass or metal on cars…falls to below freezing. Conversely…since frost does not easily form in the presence of clouds and/or wind….freezing temperatures may not result in frost. Conversely…the occurrence of frost…even in the absence of a freeze… can damage certain crops and vegetation.

In Shreveport…the earliest first freeze occurred on October 19, 1989. The latest freeze did not occur until January 30, 1932. At the time of this writing…10/17…temperatures have only reached the freezing mark in far northern fringes of the Arklatex on the early morning of Friday October 13th…with the coldest temperature of 29 recorded in Battiest Oklahoma. On this same night…the coldest temperatures of the season so far were reached at Shreveport LA(46 F)...Texarkana AR(38 F)…Tyler TX(46 F)…Longview TX (43 F)…El Dorado AR(35 F)…and DeQueen AR (34 F). However…due to the very isolated nature of freezing temperatures…those temperatures that briefly did reach the freezing mark were likely due to cold air drainage in valley regions…a freeze warning was not issued. The next seven day forecast…which is rather mild…does not reflect temperatures even falling into the 30s…let alone freezing.