SEASONAL VARIATIONS IN HOURLY AIR TEMPERATURE
The accompanying image is a plot of the variations in the hourly
temperatures observed at the weather station throughout the year.
The average temperature for each hour of the day at the station was
computed from the set of observed hourly temperatures for the given
station for the 30 years from 1971-2000.
The horizontal axis displays the day of the year, while the vertical
axis represents the hour of the day (in the 24-hour format and in
Central Standard Time). Isotherms (lines of equal temperature)
were computer generated and displayed using a krieging
By selecting any hour of the day and moving horizontally, the seasonal variations in that hour's temperature can be seen. The lowest temperatures typically occur in the mid winter (days 1-50 = Jan-Feb), while the highest temperatures are found in mid summer (days 180-210= July).
Moving vertically along any day, the highest hourly temperature
usually is found in early afternoon (centered at approximately 1400 or
2 PM CST), while the lowest temperatures typically occur just before
sunrise. Since the sunrise varies throughout the year, the occurrence
of these lowest hourly temperatures appearing on these analyzed plots
also reflect these seasonal variations. For example, the lowest
hourly temperatures in mid winter occur at about 0600-0700 CST (6-7
AM), while in summer, the lowest hourly temperatures are at about 0500
(5 AM) CST.
Prepared by Edward J. Hopkins, Ph.D., Assistant State Climatologist
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Latest revision: 24 April 2004
Comments on the web page ... SCO Web Administrator
URL Address: http://www.aos.wisc.edu/~sco/stations/ann_hrly_temps.html