Dear Tom,
Is average temperature for a day just the midpoint between high and low? I would think it would be more like the average of 24-hourly readings. What’s the scoop?

Thanks, Rick Weiland, Evanston

Dear Rick,

By international convention, a day’s average temperature is the average of the high and low temperatures. It is computed by adding the high and low for the midnight-to-midnight calendar day (local standard time) and dividing by two, a method agreed upon by the World Meteorological Organization as the world’s climatological standard. While more accurate values might be obtained by averaging three, six or 24-hourly temperatures, many weather stations report only a daily maximum and minimum temperature. Most climatologists agree that over an extended period, the difference between the high/low method or the hourly temperature method becomes negligible.