Here in Michigan, 2 years ago, we had a snowstorm on May 6 - got about 5 inches. And I've seen plenty days in June that felt cold enough for snow.
May 5 snowstorm on the day we closed on the house here in central Wisconsin eight or so years ago. Only a couple of inches though & it melted that day.
Yeah, 2003 and 2004 had long, wet, cold springs, which made me think of the sudden end to good weather at the beginning of the Little Ice Age (not that I was there, just read about it). Due to changes in agricultural methods since 1900, the US generated its largest ever grain crop last year, despite the crappy spring around here (Michigan).