According to Accuweather, the West experienced a stretch of record-breaking high temperatures in June and July, and another heat wave is predicted to hit the Midwest soon. All that brutal heat, they say, will have an impact at grocery stores across the country. High temperatures affect cows' energy levels; the overheated cows tend to eat less and feel "heat stress," both of which cause them to produce less milk. And when large numbers of America's cows produce less milk, the laws of supply and demand take over, and milk gets pricier.
So how hot is too hot? Well, according to Dr. Tamilee Nennich of Purdue University, a professor of animal sciences quoted by Accuweather, cows begin to experience "heat stress" when the temperature/humidity index hits 72 degrees. With temperatures in the Midwest expected to remain in the 80s and 90s through the next couple of weeks, we could be looking at a lot of cows who are too hot to produce as much milk as usual. And Accuweather says that things will get even worse in September, when heat peaks in many parts of the country.
But all of that might not be enough to keep milk prices from rising along with the mercury. So if the cost of a gallon of 2% -- or a half-gallon of rocky road -- goes up as the season wears on, don't blame your local supermarket, blame global warming.
Matt Brownell is the consumer and retail reporter for DailyFinance. You can reach him at Matt.Brownell@teamaol.com, and follow him on Twitter at @Brownellorama.
Correction: An alert reader pointed out that the previous picture included in this article was of beef cattle, not milk cows. We apologize for the mis-steak ... the moo-stake ... or rather, the error.