The Midwest has experienced a summer of rainbows, here's why

Residents from Minnesota to Ohio enjoyed another round of striking rainbows last week. Here's why the Midwest seen such a flurry of rainbows recently.

Stunning scenes have emerged from the Midwest lately, with rainbows, double rainbows, and even bolts of lightning framed by rainbows arching across the sky seemingly every evening.

Residents from Minnesota to Ohio enjoyed another round of striking rainbows last week. While rainbows aren't exactly rare, there's still a mystique about them that makes you want to pick up a camera and capture the moment.

But why has the Midwest seen such a flurry of rainbows recently? First, a quick lesson in how rainbows form.

Rainbow science

A rainbow is a multicolored arc that is made when light strikes water droplets. Commonly, rainbows are produced when sunlight strikes raindrops at the right angle. If you've ever wondered why there's such a kaleidoscope of colors in rainbows, that has to do with wavelength, the distance over which the wave's shape repeats. The colors on a rainbow come in order of their wavelength, from the longest (red), all the way to the shortest (violet). Remember that nifty mnemonic from childhood? Roy G. Biv: red, orange, yellow, green, blue, indigo and violet.

In secondary rainbows, that order is reversed with violet coming first from top to bottom. A secondary rainbow is much fainter than a primary one because the intensity of light is reduced.

Moonbows, or a lunar rainbow, are a rarer phenomenon that happens when light from the moon is refracted through water droplets in the air. Because even the brightest full moon produces way less light than the sun, moonbows are faint and rarely seen. Kentucky's Cumberland Falls State Resort Park is one place where you can find moonbows, and the park holds photography weekends to enjoy these events.

Midwest rainbows

As AccuWeather meteorologists reported, episodes of severe thunderstorms played out repeatedly over a large portion of the north-central United States throughout the summer. Many of these storms formed on the heels of a heat dome or persistent area of high pressure in the Rockies, with powerful storms with damaging winds, hail, flash flooding and lightning in states including Minnesota, Wisconsin and Illinois.

"When thunderstorms organize in this way, they can sustain themselves, cover hundreds of miles per day and last through the night," AccuWeather Senior Meteorologist Alex Sosnowski said.

According to NOAA, the 2024 U.S. preliminary tornado count from January to July was 1,495. This count is second only to the 1,501 tornadoes in 2011 for the same January-July period—a testament to the severe weather that has bubbled up in the spring and the summer.

In the Midwest, many of these severe storms struck in the evening, just as the sun was setting to the west. This led to the perfect combination of forces for rainbows and even lightning strikes framed by rainbows to occur.

While there was a cooldown in the Midwest and Northeast, with temperatures only in the low to mid-70s in places like Chicago over the weekend, beware of false fall. Indianapolis will be back in the 80s by Wednesday.