Created on Wednesday, 24 August 2016 13:50
Last Updated on Wednesday, 24 August 2016 14:38
Written by David Gardner
Often I am asked how to estimate the average daily soil temperature if soil temperature monitoring devices are not available. One method is to take the soil temperature at 11:00 AM. Based on my casual observations of weather data this would make sense. On a typical summer day, the high and low temperatures tend to be separated by about 20-25 degrees. It seems pretty reliable to add 10 degrees to the 11:00 AM air temperature, and on an average day this will be very close to the actual high temperature, which will occur at 4:00 or 5:00 PM. This is assuming no cloud cover, no warm or cold fronts, and average humidity. So, between 10:00 and 11:00 AM, the air temperature is about ¥ way between the days high and low temperature. While there is some lag between the air and soil temperatures, monitoring the soil temperature at 11:00 AM should, based on the inferences stated above, give the most reliable approximation of average daily soil temperature that a single reading can provide.