Summer months continue dry, warmer pattern under La Nina influence
State Climatologist Justin Glisan (file photo courtesy of Iowa PBS)

DES MOINES — August continued the summer weather pattern that Iowa and the Midwest have been stuck in now for some time.

State Climatologist, Justin Glisan says the pattern includes warmer conditions. “We were about one-point-three degrees above average. The average temperature across the state was a little over 72 degrees,” Glisan says. It was also drier, with rainfall averaging 3.5 inches in August.

“That’s about six tenths of an inch below average so you look at that northeastern basically quarter of the state — the only part of the state we saw above average totals — and then you look across the rest of the state deficits and that’s where we saw drought conditions intensify and expand,” he says.

Glisan says the combined numbers for the three summer months this year are very similar to 2020 and 2021. “It’s the third summer since this 2020 drought started that we’ve seen warmer and drier conditions across the state and across much of the upper Midwest. So, on the temperature side, we were about 73 degrees and that’s a little over a degree above average,” Glisan says. “So not exceedingly warm. We’ve had pockets of warm temperatures. We’ve had cold snap through summer, basically averaging out just slightly above average though for the state.”

He says June, July, and August of this year, continued the drier trend. “Coming out right about ten-point-three inches of precipitation, and that’s a little over three inches below average. And again, you look at that drought map over the last three months abroad expansion across southern Iowa, some improvement in northwestern Iowa, where we see that D-three, extreme drought category, but overall an expansion of drought.” Glisan says the drought conditions this year are not as bad as they were for the three summer months last year.

He says the La Nina weather pattern is behind the warmer, drier summers. “La Nina is a cold sea surface temperature anomaly in the Pacific. That impacts where the storm tracks that’s up over the United States. So we’re looking like this La Nina phase should hang around into winter again, this would be the third year going into the fourth year of La Nina phase hanging around,” Glisan says. He says that could lead to a warmer winter, but it’s too earlier to tell that just yet.