Climate & Weather

Atmospheric sciences help us understand and predict the weather. Learn about topics such as the seasons, why it snows, and how rainbows are formed.

Why does the sky get dark at night? Don't tell me it's just because the Earth rotates and the sun sets -- what I mean is, with all of its stars and other luminous bodies, why isn't the universe infinitely bright?

We hear about humidity in just about every weather report on the nightly news. There are several different ways meteorologists measure humidity, but relative humidity is the most common measurement. What is relative humidity, though? Find out in this

Around 1,800 thunderstorms are occurring on the Earth at any given time. However, they typically only occur in the warmer parts of the planet. Why does warm weather spawn more thunderstorms than colder weather?

I've noticed signs on the highway that warn "Bridge Ices Before Road." What causes bridges to ice before the rest of the highway?

Why is snow white? It's frozen water, and water isn't white, it's clear.

Especially in the spring and summer, there's often a strong, funny smell right after it rains. What's behind "rain smell"?

How does the aurora borealis (the Northern Lights) work? What causes it? Why can you only see it in the North? Are the myths about it producing sound true?

Every night on the news, the weatherperson reports the UV index. What is the UV index and how is it calculated?

What causes the seasons? Why are the seasons reversed in the Northern and Southern Hemispheres? And if the Earth moves in an elliptical orbit around the Sun, why don't we have two summers and two winters every year?

What is the "heat index" that the weatherperson talks about during the summer? Also, why is the air comfortable at only 80 degrees F even though body temperature is 98 degrees F?

You may have heard that you can figure out how far away lightning is by how long it takes for the thunder to arrive after you see the flash. Is this true? How do you calculate it?

Why is it colder at the top of a mountain than it is at sea level? Heat rises, and the top of a mountain is closer to the sun -- shouldn't it be hotter at the top of a mountain?

Precipitation can vary from rain to snow when the temperature is below freezing. Why does precipitation not always fall as snow when it's below freezing?

We can usually see rainbows right after a rainstorm on a warm Spring day. These giant colorful arcs stand out against the dark rain clouds. Have you ever wondered what causes this phenomena? Find out how rainbows are created in this article from HowStuffWorks.

What is "wind chill"? Does it have any effect on inanimate objects?

A tornado is one of those amazing, awesome acts of nature that simply leaves you dumbfounded -- a huge, swirling, 200-mph beast of a storm that appears to have a mind of its own.

You’ve heard the warnings about thunderstorms: Stay out of the tub, unplug your TV and don’t call people from your land line. But can you really get struck by lightning while you’re inside?

Sometimes a lightning storm heralds sightings of St. Elmo's Fire. What causes the mysterious glow sailors interpreted as a sign of salvation?