These might usually be too early for what you meant here, but it 'feels' summery when they bloom end of April/beginning of May.
Amaryllis
It's so cool and wet lately, some of the Oxalis crassipes is blooming sparsely again now, although this pic is from May, when it was in full force.
Tried to take a pic of some tall cool Alliums while they were up last month but as tall/see-through as they were, I deleted all of my tries 'cuz all I could notice in the pics was the stuff around/behind. Didn't do justice to what it's like to look at them for real.
