May 2013. I remember because I got married that weekend, it was 80 degrees when I drove home on Wednesday, and Thursday morning there was sleet/snow. The wedding was supposed to be outdoors at a local winery; luckily we were able to roll with it and do the whole thing indoors.May 2012? Cant remember the year Des Moines got about 5” of the wet heavy in the first week of May. I could be way off though I’m 43 so Twitter tells me i probably have early dementia.