We’ve all heard the phrase “the dog days of summer”. But where did this phrase come from?

We use the phrase to refer to those hot and humid days of mid-summer, but it originates from ancient Greek culture. It was related to the rising of the star system Sirius, which in Hellenistic astrology was the dog constellation and was associated with heat, drought, sudden thunderstorms, lethargy, fever, mad dogs, and bad luck.

The playwright Noel Coward famously penned that “only mad dogs and Englishmen go out in the midday sun”. Dogs aside, with many of us camped in our homes during the COVID-19 crisis, air conditioning bills have been shocking to many. While you may be using less gas, in many areas of the country your A/C is running full tilt all day long.

We looked at some maps measuring the “Annual Cooling Degree Days” from the AGS library. This is a measure of the relative level of air conditioning demand – a measure of how much (number of degrees over 68) and how long (number of days) air conditioning may be used.

Nothing unpredictable here – highest demand areas are the Sonoran desert (inland southern California and southern Arizona, south Texas, and south Florida). Note the effect of the Appalachian mountains, keeping temperatures more modest even into Georgia and South Carolina.

We then took average prices of electricity per kilowatt hour by state and computed a relative index of the cost of air conditioning.

Prices in California are substantially higher than in Arizona, Texas, and Florida, so the relative cost of cooling your palace during the COVID-19 are much more onerous on Californians living in the desert areas like Palm Springs, Barstow, and Blythe.

Source of the pricing data was the United States Energy Information Administration.