The weather this summer in Iowa has been on the warm side for the most part. “Not so much July which the crops just came through, although we did have some hot and humid weather at times during the month,” says Harry Hillaker, state climatologist with the Iowa Department of Agriculture. “Overall, July 2016 went into the record books as about normal for temperature or just a hair below normal.”

Corn crop made it through pollination period in good shape

BIG CROP COMING? Corn and soybeans in Iowa are doing quite well for this time of year, says state climatologist Harry Hillaker. Timely rains have helped the crops grow and develop in most areas of the state, and they look good the first week of August.

For the most part Iowa has had a warm spring and summer. June was warmer than normal and got the crops developing quicker than usual, plus Iowa farmers had windows of opportunity during the planting season to get the corn and beans planted in a reasonably timely manner. So that was helpful, notes Hillaker. Some parts of western Iowa had trouble with wet weather during the last half of April and the beginning of May. But overall for Iowa, it’s been a pretty favorable year.

“We were worried in early to mid-July when we had high pressure forecast to be moving in and bringing big-time heat. But we lucked out as the high pressure didn’t stick around all that long, and most areas got some real good rain right before that heat came,” he explains. “So crops in Iowa are really doing quite well for this time of year.”

El Niño weather pattern has now shifted to neutral in mid-2016

What happened to El Niño and La Niña? Where are we at now in the weather cycle? “When we look at years where we’ve had El Niño at the beginning of the year, which is certainly the case in 2016 when we had a very strong El Niño event in place back in January, the expectation was it may switch from El Niño to La Niña weather pattern,” says Hillaker. “The question was when. Would it be after mid-summer and corn pollination time? Or later? El Niño typically is strongest during our northern Hemisphere winter. So you expect it to decline or even go away all together by the time you get to the summer months.”

El Niño has gone away now, says Hillaker. “It hasn’t actually gone all the way to the other end of the spectrum, to La Niña. It’s now what we call neutral, kind of in between the two extremes. But just looking at years when we have an El Niño event to start the year like we did this year, very often, almost 70% to 75% of the time, we get a warmer than normal spring and a warmer than normal summer in Iowa. Certainly this year it’s been both of those. We did get the warmer than normal spring and summer. And that’s very typical of years that start off with an El Niño.”

High overnight temperatures were a concern in previous years

How many overnights had higher than normal temperatures during July 2016? Not that many, although there were some. That statistic, agronomists say, is one of the big concerns. Because the daylight heat causes problems but it makes it even worse on the crop if you have warm temperatures in the overnight hours.

“That was a concern in some of the previous years,” notes Hillaker. “And that’s generally been the trend in Iowa, partly because we’ve been getting more rainfall which helps suppress daytime temperatures. You don’t get as much heating from sunlight during the day because there’s so much moisture around to evaporate, and also the higher humidity keeps the nighttime temperatures higher than they would otherwise be. So humidity results in somewhat cooler days and warmer nights.

That’s been the trend going on now for several decades in Iowa, he says. Iowa is getting warmer nighttime temperatures this time of year and really not difference on daytime summertime temperatures.

No weather problems foreseen for the rest of this summer

Looking ahead for the rest of this summer, is there anything to watch for that concerns Hillaker as a climatologist? “Nothing too concerning at this point,” he says. “We’ve had a few warm, humid days again this week. And not quite as hot as what we saw during the third week of July where we had heat indexes of up over 110 degrees F for four days in a row in some parts of the state.

“So, this week aren’t looking at things quite that warm but it is still been quite warm and very humid,” he adds. “But it doesn’t look to be lasting an extended period of time. By this weekend temperatures are forecast to be back to seasonal once again, with several chances of rain here and there. As far as we can see in the forecast for the next week to 10 days anyway. So timely rain looks to be continuing to come.”

Iowa had rather dry week during the last week of July across Iowa. Half of the state didn’t get any rain that week, the week ending July 31. Isolated amounts, maybe an inch or two here and there. “But statewide it was our driest week in 11 weeks,” says Hillaker. “On Monday, August 1, this week got off to a much wetter start, certainly in southwest Iowa on Monday morning. The area around Mt. Ayr in southern Iowa had 4.25 inches or more of rain that morning and more rain after that as well. So some rain moved across southern Iowa this week. Hopefully, we can keep the timely showers coming, as we still can use rain in much of the state as corn has just come through pollination and soybeans are filling pods.”