Have hunted Nebraska within eyesight of South Dakota the last two years on the final week of May. Both years have been exceptional, but the toms were not easy to get to play, as Smith said they're not near as interested, but you can still get that switch to flip.
Last year it took a midday shower and thunderstorm that was just one big black cloud for 15 minutes on what was the rest a sunny day. That had them all sorts of fired up for some reason.