It’s Hot, But How Hot Is It?

Five and ten year average highs for June 17 since 1970.

I asked someone yesterday if they knew what the forecast was for today. They said, “It’s gonna be hot. The high is supposed to be 106.”

And, wow, that sounds hot. Actually, is hot. Not “sounds.” Really, that’s hot.

So, the short answer is, “Yes, that’s hot for June 17.” The longer answer is more nuanced.

If you look at the high temperature for every June 17 back to 1970 (50 years), you find the five and ten-year average hits 90 or higher many times. It’s true today’s high will be the highest “June 17” temperature for the last 50 years – but even WITH it, the five and ten year averages are below where they’ve been.

You may recall the insane heat during the summer of 1995. It was an “historic” heat wave that crushed the country – including Blair.

Intense heat overspread Iowa on July 12, 1995, and lasted well into the evening of July 14th.  Dew point temperatures ranged from the upper 70s to the middle 80s through much of the time.  The highest dew point readings were over the east half of the state.  Winds remained light through the period and were generally less than 10 mph.  High temperatures during the period were generally in the 98°F to 108°F range.  The highest known temperature was 109°F in the Council Bluffs area.  Most of the west half of the state broke the century mark on the 13th, and nearly every station by the 14th. Overnight low temperatures struggled to reach the middle 70s, with some areas remaining around 80°F.  The highest heat indices were in the east half of Iowa, where the higher dew point temperatures were.  The highest reading came from Cedar Rapids, IA on the 13th, with a heat index of 131°F by late afternoon.

https://www.weather.gov/dvn/07171995_summerof1995heatwave

Is it hot today? Absolutely. Is is unusually hot? For June 17th, yes. But, does it mean more?

The numbers say, “Not yet.”

Does this mean “global warming” or “climate change” is or isn’t real? No. This data suggests , yes, it will be hot today, but the trend isn’t unusual…

…yet…