A cool and very dry airmass settled in over the Rio Grande Valley and Deep South Texas following a cold front that arrived early on January 2nd. Arctic air was pushed south by a 1034mb high that settled over northern Texas. As the wind calmed during the night, it led to temperatures falling into the 20s across much of the area, excluding the immediate coast and the southern portions of the lower and mid Valley and southeastern upper Valley (Cameron County and urban areas in southern Hidalgo County).
A Hard Freeze, defined as temperatures at or below 27 degrees for 2 hours or more, occurred generally in all rural locations north of Interstate Highway 2 in Hidalgo County, and all other locations across the Deep South Texas ranch and brush country west to the Rio Grande Plains. The freeze/hard freeze followed a record-shattering warm December and New Year's Day, and began a multi-month trend of below average temperatures.

Frost/Freeze in NORTHERN HIDALGO COUNTY, TEXAS
From 03-JAN-22 00:00:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Temperatures fell below freezing around Midnight and remained below freezing until 8:30AM. Low temperatures fell into the middle 20s across the area. A minimum temperature of 24 degrees was observed at the Linn-San Manuel RAWS site. An NWS cooperative observer in San Manuel recorded a low temperature of 25 degrees.

Frost/Freeze in INLAND KENEDY COUNTY, TEXAS
From 03-JAN-22 00:00:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Temperatures fell below freezing around 12:00AM and remained below freezing until 8:30AM. Low temperatures fell into the lower to middle 20s with a NWS cooperative observer in Armstrong reporting a low of 25 degrees. A minimum temperature of 21 degrees was reported at the Sarita Union Pacific Railroad (UPR) mesonet site.

Frost/Freeze in JIM HOGG, TEXAS
From 03-JAN-22 00:05:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Temperatures fell below freezing around 12:05AM and remained below freezing until 8:30AM. The Hebbronville airport recorded a low of 25 degrees. The Hebbronville Remote Automated Weather Station observed a minimum temperature of 24 degrees.

Frost/Freeze in BROOKS, TEXAS
From 03-JAN-22 00:35:00 to 03-JAN-22 14:55:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Temperatures fell below freezing around 12:35 AM on January 3rd and remained below freezing until 8:55 AM. Low temperatures fell into the lower to middle 20s across the area. A minimum temperature of 23 degrees was observed at the Brooks County Airport.

Frost/Freeze in SOUTHERN HIDALGO COUNTY, TEXAS
From 03-JAN-22 01:30:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Temperatures fell below freezing around 1:30AM and remained below freezing until 8:30AM. Low temperatures fell into the upper 20s to around 32 degrees away from urban areas in southern Hidalgo County. A minimum temperature of 27 was observed at the South Texas International Airport 11 miles north-northeast of Edinburg. The RAWS site at Santa Ana National Wildlife Refuge along the Rio Grande observed a low of 26 degrees. Meanwhile, the ASOS station at McAllen International Airport only reported a low of 35 degrees.

Frost/Freeze in STARR, TEXAS
From 02-JAN-22 22:11:00 to 03-JAN-22 14:11:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Temperatures fell below freezing around 10:11 PM on January 2nd and remained below freezing through 8:11 AM on the 3rd. Low temperatures fell into the lower to middle 20s across the area. A minimum temperature of 23 degrees was observed at the Falcon Lake RAWS site. The mesonet site six miles northwest of La Gloria recorded a low of 22 degrees.

Frost/Freeze in ZAPATA, TEXAS
From 03-JAN-22 00:00:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Temperatures fell below freezing around 12:00AM and remained below freezing until 8:30AM. Low temperatures fell into the lower to middle 20s across the region. A minimum temperature of 23 was observed at the Zapata airport.

Frost/Freeze in WILLACY, TEXAS
From 03-JAN-22 01:30:00 to 03-JAN-22 08:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Temperatures fell below freezing around 12:05AM and remained below freezing until 8:30AM. The Yturria Union Pacific Railroad mesonet site (UR295) in northern Willacy County recorded a minimum temperature of 26 degrees. Given low temperatures in the middle to upper 20s observed in adjacent northern Hidalgo County and Inland Kenedy County, it is implied that temperatures across much of Inland Willacy County were also in the middle to upper 20s.