I'm originally from Las Cruces, NM, (45 miles north of El Paso). We stayed six weeks in the area over the holidays this past winter. It got down into the teens several times and we had snow the day after Christmas. The difference between the El Paso area and the lower Rio Grande Valley is about 3,500 feet in elevation and several degrees of latitude. El Paso also has a crime problem being on the border with Juarez, as well. It's not a place I would choose to winter if I didn't have family in the area.
Rob