Chilling Hours / First Frost

Chilling Hour Accumulations
The dormant buds of many plants require a period of cold weather to grow, flower, and develop properly, but requirements vary widely by species. For dormant buds of fruit trees, this is commonly referred to as the chilling requirement. Chilling hours are calculated as a tool for fruit producers to gauge whether their crop has been exposed to cold temperatures for a long enough time period. This table shows chilling hours as recorded at the Overton Center and should provide you with an estimate of chilling hours if you live in northeast Texas.
Chilling Hours for the 2012-2013 Season
thru February 28, 2013
Method 1
No of Hrs >=32
&<=45 F		 Method 2
No of Hrs <=45 F
Oct 47 47
Nov 129 158
Dec 183 280
Jan 248 315
Feb 194 203
TOTAL 801 1003
Temperatures can fluctuate from one location to another, however, so the number of chilling hours at your peach orchard may be different than what we have recorded here. For chilling hour data from past years, see the table below. Several methods exist for calculating chilling hours; two are presented here.
Calculating Chilling Hours
Method 1: Chilling hours were calculated by counting the number of hours between 32 and 45 degrees F, from October 1st through February 28th/29th. Method 2: Chilling hours were calculated by counting the number of hours at or below 45 degrees F, from October 1st through February 28th/29th.
Historical Date of First Frost and Chilling Hour Data
Season Date of First Frost First Frost Temperature
(F)		 Chilling Hours Method 1 Chilling Hours Method 2
2012-2013 Nov 13, 2012 (4 a.m.) 31.8 801 1003
2011-2012 Nov 28, 2011 (3 a.m.) 30.4 867 980
2010-2011 Nov 6, 2010 (8 a.m.) 31.9 819 832
2009-2010 Dec 4, 2009 (11 p.m.)
Dec 3, 2009 (7 a.m.)		 25.6
32.6		 1067 1440
2008-2009 Oct 28, 2008 (7 a.m.) 30.9 789 992
2007-2008 Nov 23, 2007 (7 a.m.)
Nov 16, 2007 (7 a.m.)		 31.6
32.5		 974 1156
2006-2007 Nov 3, 2006 (7 a.m.) 30.6 907 1218
2005-2006 Nov 17, 2005 (7 a.m.) 27.0 818 993
2004-2005 Nov 30, 2004 31.1 726 909
2003-2004 Nov 24, 2003 31.4 845 1046
2002-2003 Nov 28, 2002 28.5 1060 1227
2001-2002 Nov 21, 2001 30.1 855 1045
2000-2001 Nov 10, 2000
(Oct 10, 2000)		 30.4
(32.7)		 1178 1491
1999-2000 Nov 5, 1999 31.8 563 728
1998-1999 Nov 2, 1998 29.7 574 687
1997-1998 Nov 15, 1997 26.6 - -
1996-1997 Nov 27, 1996 30.2 849