A strong cold front swept across Deep South Texas and the Lower Rio Grande Valley during the overnight and early morning of December 9th and 10th, bringing periods of sustained gale force winds to the Laguna Madre and adjacent Gulf of Mexico waters out 20 nm, as well as a prolonged period of sustained winds of 30 mph with frequent gusts between above 45 mph, generally between 9 PM on the 9th and 6 AM on the 10th, most pronounced near the coast.
Behind the front, temperatures struggled through the 50s despite ample sunshine on the 10th, setting the stage for the first freeze of the young winter the following morning.

Frost/Freeze in HIDALGO, TEXAS
From 11-DEC-08 06:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: Park/Forest Service

Clear skies and light winds allowed temperatures to plummet across mainly rural northern Hidalgo County during the morning of December 11.  At the Linn-San Manuel Mesowest (RAWS) observing station, part of the Lower Rio Grande Valley National Wildlife Refuge, the temperature fell to 30 degrees just after 7 AM.  While this location is just over the county line in extreme northwest Willacy County, interpolation between this location and the Falfurrias, TX (Brooks County) cooperative station argue for at least two hours of 32 degree F or lower readings, generally north of an Edinburg-Alton line.

Frost/Freeze in JIM HOGG, TEXAS
From 11-DEC-08 06:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Clear skies and light winds allowed temperatures to plummet across mainly rural central and southern Jim Hogg County during the morning of December 11.  While temperatures at higher terrain, generally above 500 feet, may not have reached freezing, lower elevations likely fell to or below 32 for at least two hours just prior to sunrise, based on interpolation between similar cooperative observations at least a cooperative station (Brooks County, to the east), and one airport location (Zapata County, to the west).

Frost/Freeze in BROOKS, TEXAS
From 11-DEC-08 05:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: COOP Observer

Clear skies and light winds allowed temperatures to plummet across much of Brooks County during the morning of December 11.  At the Falfurrias, TX, cooperative station, located at the Hollywood Hunting Camp just west of town, the low fell to 28 degrees. Interpolation with nearby stations, as well as the generally low and flat terrain of much of the county, suggest at least 3 hours of temperatures at or below 32 degrees Fahrenheit.

Frost/Freeze in KENEDY, TEXAS
From 11-DEC-08 05:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: COOP Observer

Clear skies and light winds allowed temperatures to plummet across large portions of the King Ranch in Kenedy County during the morning of December 11.  While two cooperative stations are normally cooler than most, even these stations were significantly cold enough to justify a more widespread freeze.  At the retreat 7 miles east of Sarita, a record low for the date of 25F was set, and the observing post at Armstrong, about 20 miles to the south, dipped below 30F.

Frost/Freeze in ZAPATA, TEXAS
From 11-DEC-08 05:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: AWOS

Clear skies and light winds allowed temperatures to plummet across much of Zapata County during the early morning of December 11.  At the airport just northeast of Zapata, located in a normally colder location, temperatures fell to 32 or lower for nearly 3 hours.  Zapata airpor's low was 30 or 31, at around 6 AM.  Also, the morning low reached 27 degrees (2 meter temperature) at the Falcon Lake Mesowest-RAWS location, in extreme western Starr County just east of the Zapata/Starr County line.
It can be assumed that other similar locations, particularly across the western half of Zapata county, had similar conditions.

Frost/Freeze in WILLACY, TEXAS
From 11-DEC-08 06:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: COOP Observer

Clear skies and light winds allowed temperatures to plummet across rural Willacy County, particularly west of highway 77, during the early morning of December 11.  At the cooperative station near Raymondville, temperatures bottomed out at 31 degrees; the observing station (Mesowest-RAWS) at Linn-San Manuel, at a wildlife area managed by teh Lower Rio Grande Valley National Wildlife Refuge system, dropped to 30 a little after 7 AM.  Interpolation between these two readings argues for some locations falling even lower for a longer period of time, including some agriculturally sensitive areas.

Frost/Freeze in STARR, TEXAS
From 11-DEC-08 05:00:00 to 11-DEC-08 08:00:00 (CST-6)
Property damage: 0.00K
Reported by: Park/Forest Service

Clear skies and light winds allowed temperatures to plummet across Starr County during the early morning of December 11.  Based on surrounding observations in Zapata (to the west) and along the Hidalgo/Willacy County line (to the east), it can be argued that for large swaths of generally lower terrain across the northern/western two-thirds of Starr County had at least 2 hours of temperatures at or below 32F.
At the Falcon Lake Mesowest-RAWS observing station just east of Falcon Lake, near the Zapata County line, the temperature fell to 27 degrees a little after 6 AM, with several hours at or below 32 degrees.