Mother Nature set the thermostat in the 90’s and left it there. That’s one way to sum up State Climatologist Harry Hillaker’s review of the weather for July.
Hillaker says it looks like the temperatures for July will average out about five degrees above normal for the month, which he says doesn’t sound like a lot, but it was the warmest July since 1955. He says it was the warmest of any calendar month since August of 1983.
Overall it ranked as the seventh warmest July and 10th warmest of any calendar month on record. Hillaker says there weren’t many record highs, just constant heat. He says all but five days averaged warmer than normal, but there were not many extreme temperatures, with the 102-degrees on July 18th the highest official reading.
“Basically just a case of very persistent warm weather,” Hillaker says. Des Moines did have a string of 13 straight days of 90-degree or hotter days. There was enough moisture added to the heat to make the heat index higher than normally felt during July.
Hillaker says there was an official heat index reading of 117 in Spencer on July 18th and unofficial heat index readings of 130 in some places. He says there were six days where the heat index was officially 110 or higher — while many years we never get that high — so it is “quite unusual.”
Rainfall was just under an inch below normal (.88), but Hillaker says the amount of rainfall continued to vary widely. He says it’s no surprise that Dubuque was the wettest spot in the state in July, with just over 16 inches for the month, marking the most rainfall in any one month in 158 years of records. That includes a record 24-hour rain total of 10.62 inches near the end of the month.
While Dubuque had an overabundance of rain, other areas could have use some of the excess. “Especially some parts of southeastern Iowa, Fairfield for example has only 17-hundredths of an inch of rain for the month of July, which is extremely dry for any location in Iowa for a summer month,” Hillaker says. He says there were scattered locations such as Creston and Albia that also had less than an inch of rain.