UPDATE: Temps sank as low as 15 degrees in Travis County during freeze

10:30 a.m. update: Just how cold was it overnight? The National Weather Service has released some startlingly chilly temperature readings for the freeze that gripped Central Texas early Wednesday. Here are some of the coldest:

• Travis County: 15 degrees at Wells Branch; 19 degrees near Jonestown; 20 degrees near San Leanna; 21 degrees near Briarcliff; 22 degrees in Bee Cave; 23 degrees in Lakeway and Lago Vista; 24 degrees at Austin-Bergstrom International Airport (new daily record); 29 degrees at Camp Mabry.

• Williamson County: 21 degrees in Florence and Liberty Hill; 22 degrees near Andice and in Hutto; 23 degrees near Brushy Creek; 24 degrees in Taylor and Georgetown; 25 degrees in Granger; 26 degrees in Round Rock.

• Bastrop County: 22 degrees at Camp Swift and Bastrop; 23 degrees near Wyldwood; 24 degrees at Cedar Creek; 26 degrees near Rosanky and Dale.

• Hays County: 17 degrees near Fischer; 19 degrees in Driftwood; 20 degrees in San Marcos; 21 degrees in Buda; 22 degrees in Wimberley.

Wednesday forecast for Austin: One day more — another day of cold, possibly freezing temperatures are on deck for Central Texas before warmer temperatures move in for the rest of the week, the National Weather Service said.

Temperatures during the day are expected to reach a high near 54 degrees, before dropping to a low around 32 degrees at night, forecasters said. A freeze warning issued by the National Weather Service was in effect until 9 a.m. for areas along the Interstate 35 corridor and the Hill Country, including Travis, Hays, Bastrop, Williamson, Caldwell, Burnet, Blanco, Llano and Gillespie counties.

Austin-Bergstrom International Airport recorded a temperature of 24 degrees at 5:50 a.m., breaking a record low of 25 degrees set in 2014, forecasters said.

At 6:30 a.m., temperatures at Camp Mabry were reading at a freezing 32 degrees, while locations farther away from the urban core of Austin were largely in the 20s:

• 21 degrees near Lago Vista

• 23 degrees at San Marcos Municipal Airport, Hays County

• 23 degrees in Oak Hill, southwest Travis County

• 27 degrees at Georgetown Municipal Airport, Williamson County

• 27 degrees in Pflugerville in northeast Travis County

Wednesday will be the last time temperatures will in the 30s — at least through next Tuesday, according to the weather service's extended forecast. Prepare for warmer days with milder temperatures:

Thursday: Sunny with a high near 64. Mostly clear at night with a low around 41.

Friday: Sunny with a high near 68. Clear at night with a low around 44.

Saturday: Mostly sunny with a high near 70. Mostly cloudy at night with a low around 53.

Sunday: Mostly cloudy with a high near 64 and a 30 percent chance of rain. Cloudy at night with a low around 46 and a 30 percent chance of rain.

Monday: Cloudy with a high near 56 and a 40 percent chance of rain. Cloudy at night with a low around 48  and a 30 percent chance of rain.

Tuesday: Cloudy with a high near 61 and a 40 percent chance of rain.