A dry cold front whipped across Deep South Texas during the morning of November 30th, bringing very low humidity along with much cooler temperatures compared with the prior day.  Clear skies and calming winds allowed temperatures to plummet rapidly across the drying soils of large swaths of ranchland and brush country, including portions of the mid and upper Rio Grande Valley.  Temperatures would bottom out in the mid and upper 20s in preferred colder spots, and around 30 to near freezing in slightly warmer locations, with freezing temperatures lasting anywhere from 4 to 9 hours.
The second freeze in less than a week continued the rapid pace of grass and brush curing.

Frost/Freeze in HIDALGO, TEXAS
From 01-DEC-10 03:00:00 to 01-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: COOP Observer

Rural areas of Hidalgo County, accounting for more than half of the surface area, fell to or below freezing for several hours after midnight and just beyond daybreak.  The Remote Automated Weather Station at San Manuel dipped to 26 degrees for nearly 8 hours; the location at Santa Ana National Wildlife Refuge east of Pharr fell to 29, with 5 hours of 32 degrees or lower.  The cooperative observer at San Manuel recorded 30 degrees.  Populated centers in south Central Hidalgo County remained just above freezing.

Frost/Freeze in ZAPATA, TEXAS
From 01-DEC-10 00:00:00 to 01-DEC-10 09:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Temperatures dipped to 32 just before midnight on December 1st at Zapata County Airport near Medina, and would fall farther, reaching 24 degrees before daybreak.  At Falcon Lake Remote Automated Weather Station in Starr County, just across the County Line, recorded 24 as well, with 7 hours of freezing or below temperatures.  The Falcon Dam cooperative site also fell below freezing, reaching 31 degrees for a few hours.

Frost/Freeze in STARR, TEXAS
From 01-DEC-10 01:00:00 to 01-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Temperatures dipped to 32 just after midnight on December 1st at the Falcon Lake Remote Automated Weather Station in western Starr County, just across the Zapata County line, bottoming out at 24 with 7 hours of freezing or below temperatures.  The nearby Falcon Dam cooperative site also fell below freezing, reaching 31 degrees for a few hours, and Rio Grande City reached at least 30 degrees at around daybreak.  Similar temperatures are assumed to have occurred across the bulk of the county north and northeast of these locations, based on these and other proxy observations.

Frost/Freeze in KENEDY, TEXAS
From 01-DEC-10 02:00:00 to 01-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: COOP Observer

The cooperative observer at Armstrong (southern portion of the county) and east of Sarita, at the Lebh Shomea House of Prayer, recorded low temperatures of 26 and 28 degrees, respectively, around daybreak on December 1st.  Based on Automated Weather Observing System and Remote Automated Weather Stations in Brooks and Hidalgo County, as well as the Automated Surface Observing System at Kingsville (dropping to 29 degrees for two hours), interpolated information suggest up to 6 hours of freezing temperatures on the King Ranch.

Frost/Freeze in JIM HOGG, TEXAS
From 01-DEC-10 03:00:00 to 01-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Temperatures dipped to 32 for just under 3 hours at the Jim Hogg County Airport northwest of Hebbronville. [The cooperative site was unavailable as of this writing].  Based on proxy observations in Brooks, northern Hidalgo, Starr, and Zapata County, interpolation among them suggest low temperatures across much of the County may have reached the upper 20s, with freezing temperatures lasting up to 5 hours.

Frost/Freeze in BROOKS, TEXAS
From 01-DEC-10 02:00:00 to 01-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Temperatures dipped to 32 by 3 AM at the Brooks County Airport just east of Falfurrias before the sensor went out of service.  The low temperature at the cooperative site at Hollywood Hunting Camp was 31 degrees; proxy observations from Kenedy County (Sarita; 28 degrees and Armstrong; 26 degrees) as well as Linn/San Manuel (10 miles south of the County line) which also dropped to 26 degrees with 8 hours of freezing or below, can be interpolated to assume widespread, long duration freezing temperatures elsewhere in Brooks County.