A rainbow at 10 p.m.? It’s possible in Alaska during the months of midnight sun, when summer days stretch long and night is a mere suggestion. Summertime is Denali’s wettest season, too. Park spokesperson Kris Fister says, "Rainbows are a regular occurrence," though Mount McKinley is often veiled in clouds. From the towering mountain and its surrounding peaks, icy ribbons of glaciers spill into floodplains that become highways for wildlife such as wolves, caribou, moose, lynx, and grizzly bears. But not cars; nearly all of the 6-million-acre park is offlimits to them. A shuttle bus delivers you to this spot at the Teklanika River Bridge. (907) 683-2294, nps.gov/dena.

Can’t get there? Here’s another
There are rainbows aplenty to chase in Hawaii—the Rainbow State—but Kauai, the rainiest island, gets more than its share. On foot you can see them near the misty Na Pali cliffs; from aboard a helicopter you may spot a 360-degree streamer of colors. kauaidiscovery.com.