After what seems like forever to most of us, this past week finally brought some relief from the almost uninterrupted heat and humidity of July and early August.
One way to measure the degree of discomfort of such a spell is to examine how many overnight low temperatures dropped below 60 degrees. In order for the overnight low to get below 60 degrees, the dewpoint temperature (which we have discussed as a measure of human comfort in this column before) must also get below 60 degrees.
Our sense is that most people begin to notice the humidity when the dewpoint is 60 degrees, are somewhat uncomfortable when it is 65 degrees, and are downright miserable when it is at or over 70 degrees. Perhaps not surprisingly, no one remembers June 2011 as particularly muggy, the month had 18 days on which the overnight low dropped below 60 degrees.
July, on the other hand, had only five such nights and, through Aug. 10, only one such night has occurred this month. Thus, beginning June 30, we have had only six out of the last 42 days with dewpoints low enough to drop the overnight low temperature to below 60 degrees. That is pretty darn oppressive!
During that same stretch, we have been 4.97 degrees above normal in temperature and 2.5 inches below normal in precipitation. That further testifies to the heat and the fact that it has not been broken up by many cooling thunderstorm events here in Madison.
Over the next 10 days or so it appears that we will continue to enjoy a relief from the hot July so the worst may be behind us.