December, a month that brings the end of Fall and the beginning of Winter, ended up bringing a few changes to the Fall Weather Trends of 2004. For starters, it brought the 2nd winter precipitation event of the year to the area from the late afternoon of the 24th to the early pre-dawn hours of December 25th. Measurable snow fell over the southeast part of South Central Texas. The other snow event in 2004 was February 13th and 14th. The February event affected the Texas Hill Country to parts of Central Texas, including Austin, and over adjacent areas of South Central Texas. After waves of severe weather and floods during October and November, December 2004 brought much drier weather and more sunny days. December 2004 ended up the 3rd driest of record, 1942 to 2004, for Austin Bergstrom; the 5th driest of record, 1871 to 2004, for San Antonio; and the 10th driest of record, 1856 to 2004, for Austin Mabry. In early November, drier weather tried to get started only to break down as more rain, clouds, severe weather and floods came. This ended the day before Thanksgiving, and a drier than normal weather trend followed through most of December. This was briefly interrupted by cloudy skies and light rain the first weekend of December on part of the 4th and all day the 5th, and by a brief period of cloudy and cold weather the 22nd to the 24th, when a winter precipitation event came to the southeast part of South Central Texas. Widely scattered showers, with light rain amounts, tried to get started over the east part of the area on December 31st, then diminished by evening.

December 2004 also brought some much colder temperatures, the coldest of 2004. The cold front of November 30th, left cold lows the 1st, followed by two strong Cold Fronts on the 13th and 14th, and another on the night of the 22nd and day of the 23rd. The surge of Arctic Air just before Christmas came in several wave, that made it colder from Wednesday the 22nd to Christmas Eve the 24th. A warming trend ended the month from the 26th to the 31st. On the 31st, afternoon highs rose to near December 9th and 12th daily maximums, with highs in the 70s to near 80. December and the Year 2004 ended with above normal temperatures. This is the way 2004 began in January, warm and humid.

In wake of a strong cold front on November 30th, freezing temperatures showed up on December 1st, over the Texas Hill Country and adjacent parts of South Central Texas. Only the southeast part of South Central Texas escaped the freeze on the 1st. After the 1st a warming trend followed, then changed to cloudier days the 3rd through the 5th. After light rain, skies cleared up late in the day of the 6th, and warmer afternoons followed. Highs warmed to the upper 70s and lower 80s by the 9th, followed by cooler conditions on the 10th, in wake of a dry cold front. Dry conditions prevailed the weekend of the 11th and 12th. After a warm afternoon on the 12th, much colder weather followed on the 13th, in wake of a strong cold front the night of the 12th and morning of the 13th. This caused a freeze to part of the area on the 14th, and a widespread freeze to the Texas Hill Country and all of South Central Texas on the night of the 14th, and morning of the 15th.

After a sunny day on the 15th, clouds increased the night of the 15th to cloudy conditions the 16th. Only light precipitation amounts fell the 16th, before conditions cleared late in the afternoon of the 16th. Sunny and pleasant conditions came the 17th, and the dry pattern prevailed through the 19th. On the 20th and 21st conditions warmed up ahead of a cold front, that brought much colder weather the 22nd to the 25th. Several surges of Arctic air caused temperatures to fall from the 22nd to the 24th. By the 24th, daytime highs could only make it to the 30s, with some locations near 30 over the Texas Hill Country. A winter precipitation event came late the 24th and in the early morning of the 25th over South Texas and parts of Southeast Texas, associated with a low aloft that moved from the Rio Grande south of Eagle Pass to the Coastal Bend. Over South Central Texas, snow came to mainly the southeast part of South Central Texas. From the late afternoon and early evening of December 24th, 2004 to the early morning of December 25th, 2004, measurable snow was observed over the southeast part of South Central Texas. The area was over parts of Atascosa, Wilson, Karnes, Dewitt, Gonzales, and Lavaca Counties. The heaviest snow amounts were from the southern part of Atascosa County to Karnes, Dewitt, and Lavaca Counties. Snow also fell further south over the Coastal Bend, and Lower Rio Grange Valley, and east to parts of Southeast Texas. A brief period of snow flurries and sleet was observed over parts of Bexar and Guadalupe Counties in the late afternoon to very early evening hours of December 24, 2004. During this event, snow was not observed at Austin, Del Rio or San Antonio International Airport. With the December 24 and early morning of December 25, 2004 snow event Kenedy had 6 to 8 inches, Runge 7 inches, Cuero 3 to 6 inches, Yorktown 6 inches, Karnes City 5 inches, between Kenedy and Karnes City 3 to 4 inches, Speaks 2 inches, Falls City 1 inch, and Yoakum 1 inch.

After the snow event during the day of Christmas Day clear skies prevailed, followed by another clear and cold night with freezing temperatures, the 4th night in a row of freezing early morning lows. Clear skies and warmer temperatures showed up the afternoon of the 26th. Another freeze affected parts of the Texas Hill Country and northern parts of South Central Texas in the early morning of the 27th, making 5 freezes in a row for some locations. During the day of the 27th, a warming trend began and continued through the end of the month. Overnight lows on the last 3 days of the month, exceeded daytime highs from the middle of the previous week to Christmas Day. On the 31st, December of 2004 ended as a sunny and unseasonably warm day with highs in the 70s to near 80.

After an unusually wet year, December 2004 was much drier than normal. Since 1970, this has also occurred in 1973, 1981, and 1985. This also showed up in 1998, after a wet winter, very dry spring and summer, and very wet fall. Monthly rainfall amounts in December 2004 were mostly less than three quarters of an inch, with some isolated amounts near one inch. Rainfall was less than a quarter inch over the southwest part of South Central Texas and extending to east of San Antonio. Amounts between a quarter inch and an inch fell from near Del Rio to the northern Texas Hill Country; over parts of Central Texas; and over the east and southeast edge of South Central Texas. The dry month came after rainfall amounts of 20 to 30 inches fell over the north and east half of the area from October 1st to November 30th. The average temperature ended up cooler than normal from Del Rio to parts of the Hill Country and parts of Central Texas to near and slight above normal the rest of South Central Texas. If it had not been for the pronounced warming trend in the early part of the month and at the end of the month, below normal monthly temperatures would have prevailed for the entire area.

The average December temperature was 53.1 degrees, 0.7 degrees above normal. The average high was 65.3, and the average low was 41.0. Heating degree days 368 and cooling degree days 8. The highest temperature reached 81 on the 9th, and the lowest was 24 on the 25th. Highest wind gust was 41 mph from the north with a cold front on the 22nd. Rainfall was 0.08 inches, 1.96 inches below normal. December 2004 was the 5th driest December of Record, coming after the wettest November of Record in 2004. Rainfall from January 1st to December 31st, 2004... 45.33 inches or 12.41 inches above normal. 2004 was the 6th wettest year of record, from 1871 to 2004, for San Antonio.