Year Round Gardening for Metro Houston

This 3 page file has my 2012 Winter Hardiness Zones for annual low temperature 1992-2012 in all National Weather Service Weather Stations with 10 years of data. The winter low temperature zones differ from USDA because the lows I am using are for the winter, not the calendar year. The way NWS reports things, a very cold last week in December and a very cold next week in January are treated as two different annual lows. Since we tend to swing from El Nino to La Nina events, this leads to very misleading data. As well, my tables use the last 20 years, rather than the 1975-2005 that the 2012 USDA model uses.  Since 1975-1990 had some of the coldest days and months ever in the Houston area, this is not very helpful.  As well, I take median average low temperatures at smaller intervals than 5-10 degrees. There is a big difference in fruit tree tolerances for mangoes between 28F and 25F.  Lastly, I list chill zones for the area. These are not quite the same as the low temperatures since they are based on cool temperature duration more than a specific cold night.  The last page is the USDA current zone map which is quite at odds with my data.

Randall Southeast Texas Low Temperature Zones