Coolest July ever? Most likely

In a summer with more long sleeves than short shorts, it's very possible this is the last day of the coolest July in Iowa history.

“Given the forecast for the next few days, it's probably a maybe record,” State Climatologist Harry Hillaker said Thursday.

Early returns from about 75 percent of the state's 138 official reporting sites produce a statewide daily average temperature of 68.2 degrees, 5.6 degrees below normal and 0.1 degree lower than the 1891 record. Hillaker expects that to hold when all sites have reported.

It's been even cooler, and wetter, in Eastern Iowa. The 66.3-degree daily average at The Eastern Iowa Airport is 8.1 degrees lower than normal and more than 3 degrees lower than the 2004 record. The high for July was just 83 degrees, on July 24.

Iowa City's 68.8-degree average, 8.0 degrees lower than normal, adds up to the coolest July ever at the Iowa City Airport and is 0.2 degree below the mark set in 1861. The month topped at 85 degrees July 6.

It was slightly wetter than usual statewide, thanks largely to remarkably wet weather in Eastern Iowa.

“Jones and Jackson counties in particular have probably been the wettest,” Hillaker said.

It was warmer in June (an 68.7-degree average in Cedar Rapids) than in July, another rarity that holds statewide. It was just the ninth summer that's happened in 137 years of record-keeping, Hillaker said.

The area's last 90-degree day was June 27 (91 in Cedar Rapids, 92 in Iowa City).

Where did our summer go?

“It went out west,” Hillaker said, noting that locations from Texas to the Pacific Northwest set records for July heat.

Hillaker said a northwest-to-southeast jet stream has settled over middle of the continent, bringing cool Canadian air to the Midwest.

“It's somewhat typical of this kind of weather pattern,” he said. “If some place is usually wet, another place is unusually dry. What's different this time is that it's been so persistent.”