Scientists shrug come rain and shine
Some just call it a sun shower. Others say that devils are getting married — or the rats, or that the foxes are having a wedding.
In some places, a hyena is giving birth or there’s a hole in the heavens.
And although unnerving, some casually remark that the devil is beating his wife.
These are a few ways people around the world have described the phenomenon of rain falling while the sun is shining.
You won’t find any of those terms in the American Meteorological Society’s Glossary of Meteorology, but there’s always a place somewhere on this planet where you can stumble upon this magical weather paradox. But they don’t make much of an impression on meteorologists.
“I’m not a fan of the term,” said Gary Lackmann, an atmospheric scientist at North Carolina State University. He added, “‘Sun showers’ are really just rain showers that take place with partly cloudy or broken cloud conditions, and they can occur in a few different ways.”
Often you’ll spot them when the atmosphere around you is, in meteorological terms, unstable — which is more likely during the spring and summer in many parts of the world. In this condition, temperature variations encourage columns of air to move vertically, rising rapidly in some places and sinking in others. In the rising columns, the air cools, condensing moisture within it and allowing clouds and showers to develop. But the air in the sinking columns suppresses clouds, creating areas of clear skies between showers — and the possibility of sun showers.
But you won’t see them if the sun is straight overhead. Your chances to catch the magic are greater when the sun is low on the horizon, like the midmorning or the midafternoon, or when a shower moves east. At those moments, the angle of the sun allows it to shine beneath the rain clouds. “This is also a good recipe for rainbows,” Lackmann said.
And there are less common opportunities to see sun showers, too. It can take several minutes for raindrops to fall from their cloud homes in the sky to the Earth’s surface. And in rare instances when a dissipating cloud produces rain, the sun can break through the clouds while the drops are still falling.
“That’s something you see happen in the tropics or when the [wind] is blowing and pushing the rain out from under the cloud,” Lackmann said.
In Hawaii, for instance, sun showers are known locally as pukalani, or pineapple juice. Pukalani, also the name of a rainy town, means “hole in the sky.”