What It Means If The Sky Is Green (And If It's Safe To Be Outside)

Anyone who has lived in Tornado Alley or other areas with high rates of severe weather has probably experienced the phenomenon of a green sky. It can be unsettling to the untrained eye to see the hazy greenish-yellow tint. But even many people accustomed to the look of a menacing green sky don't know what causes it. It's actually a simple process. Although not a large area of study, the phenomenon of green skies was described by Bohren and Fraser in their 1993 paper published in the American Meteorological Society. Skies typically appear blue because air particles scatter blue light during the day (thanks to their shorter, smaller waves). According to Bohren and Fraser, when storms appear late in the day, the red light from sunset makes blue things look green, hence the greenish sky of summer thunderstorms.

If your only experience with tornadoes and severe weather is the magic of movies, you might believe that green skies always herald an incoming tornado. In reality, while it's definitely possible for these green hues to appear before, during, and after a tornado comes through an area, it isn't always a sure thing and isn't very common. Green skies often just indicate a large amount of water droplets in the air and very deep clouds, combined with a big potential for heavy rain and hail. Make sure to prepare with simple ways to protect your home and outdoor space during a storm before you see green skies. Otherwise, it's often too late after storms arrive with strong winds and powerful rains.

Green skies are not a welcome sight for anyone spending time outside. Even if it's not likely that a tornado will touch down where you're at, green skies often indicate incoming severe weather. Strong rain and large hail often follow in the wake of green skies. If you are outside and you notice the sky taking on a green hue, you might want to consider seeking shelter immediately. It's important to know about tornadoes and top tips for staying safe when they appear. 

You should always try to seek shelter in the case of a tornado, but even strong thunderstorms without tornadoes can be extremely dangerous. Regardless of tornadic activity, it's very important that you find a safe spot under cover, preferably inside. If you are not able to make it to a secure spot inside before severe weather in your area, avoid tall trees if at all possible. Strong storms often bring with them plenty of electrical energy in the form of lightning, which will strike the tallest objects first in a certain location (often trees). If you like to camp during seasons with extreme weather, know how to protect yourself when tent camping during a thunderstorm. Understanding what to do when green skies occur is the best way to stay safe on your outdoor adventures.