Below-average temperatures spanned the Rockies to the East Coast
Everyone seems to be wondering, "What happened to spring?" Last month, a persistent flow of Arctic air blanketed the eastern two-thirds of the nation. Record cold, and even snow in some areas, delayed the onset of warm spring-like conditions.

Snow and iced branches along the shores of Lake Superior in the U.S. Midwest as photographed on April 17, 2018. (Image credit: Sharon Mollerus/flickr Creative Commons 2.0 license/https://flic.kr/ps/zRKVu)