Find answers to weather's mysteries.

Weather happens every day; still, it's a bit mysterious. Illinois Extension takes away some of that mystery with these short, easy to follow videos. 

• What is the Heat Index?
  Why do weathercasters talk about “feels like” temperatures in summer that are higher than the actual temperature?  Watch this video to find out.
   
• What is the Wind Chill Index?
  Why do weathercasters talk about “feels like” temperatures in winter  that are lower than the actual temperature?  Watch this video to find out.
   
• What Causes the Seasons?
  Spring ,Summer, Fall and Winter. Why do we have changes in temperature throughout the year.  The cause may be a surprise.
   
• Types of Thunderstorms
  There are several types of thunderstorms, each with their own characteristics.  This video discusses each one.
   
• Good and Bad Ozone
  We hear on the news about bad ozone that causes health problems, but also the loss of ozone over Antarctica, which also can be a health problem. Watch to learn the difference.
   
• Is Heat Lightning Real?
  You hear many people talk about heat lightning on warm summer nights. Is lightning formed from just heat?  Find out with this short video.
   
• What Makes the Wind?
  Find out how wind is created by the H’s and L’s you see on a weather map.
   
• How Does Hail Form?
  Some thunderstorms have hail, others don’t. Learn the process that creates hail in this video.
   
• How Do Clouds Form?
  Clouds come in all shapes and sizes.  Some are made of tiny water droplets, others have ice crystals. This video describes how clouds are created.
   
• What is the Greenhouse Effect?
  The Greenhouse Effect is a part of nature, but people can make it stronger or weaker.  Watch this video to get a brief description of how it works.
   
• El Nino and La Nina
  El Nino and La Nina are part of a huge natural  change in air pressure, ocean temperatures and winds in the Equatorial Pacific. Find out how these changes affect weather in the United States.
   
• How to Read a Weather Map
  Ever wonder what all the symbols mean on a weather map. Find out with this video!
   
• How the Sun Heats the Earth
  Learn the basic processes of how the sun comes through Earth’s atmosphere, heats the earth’s surface, then escapes back to space.
   
• Visible Spectrum of Light
  Humans see just a small fraction of all the energy the sun produces.  Watch this video to learn about how energy travels in waves and how the size of those waves are visible and invisible, and what actually is received on Earth.
   
• Rain Shadow: 
  The rain shadow effect is the reason why areas on opposite sides of a mountain can have drastically different climates.
   
• Temperature Inversions
  Temperature near Earth’s surface usually decreases the higher you go from the surface, but not always. Learn why there are times when temperature gets warmer at higher elevations.
   
• Derecho
  A rare but destructive wind can move over much of the United States during certain times.  Watch this video to find out what a Derecho is.