Brian since you are not in Utah the easiest, most accurate, and dependable source, is to call the FAA's AWOS* station at
Wendover airport. The information is updated no less than 4x/hr and it could be as frequent as 5-10 minutes if there are rapidly changing conditions. You get temp, density altitude, pressure, visibility, etc. I just called 435/665-2521 and the number is good. The altitude of the track and the airport are within 15 ft of each other.
National weather stations and other links get their pressure data from the closest airport unless they have a special source even closer to their reporting point. However, you can
not depend on their update frequency. With AWOS or ASOS
you bet your life on it.
*automatic weather observation system. (or other interpretations)