May: cumulonimbus

1   Incubator
2   April: the First Day of Summer
3   February: The Artic Circle
4   March: Seed Capsule
5   May: cumulonimbus
6   July: murmuration
7   August: cloudpark
8   September: The Last Day of Summer
9   October: Cerberus
10   November: eleven
11   December: polarisation