Page 2
Climate vs. Weather

For many of us, it has become second nature to be interested in the weather on any particular day. It is convenient to know if rain is on the way, if a cold front is moving in, or if a large event might interrupt our daily lives. The record of our experience with weather becomes our expectation of climate. Though we might not think about it as often, people in Georgia expect the winters to be mild, people in New Mexico expect summers to be hot and dry, and those in Montana expect some snow by Christmas.

Weather varies from hour to hour and from day to day. Climate is defined as the average of weather over several decades or longer. Scientists study the Earth's climate in a very similar way to weather, but with an emphasis on longer time scales. Climate questions are different from weather questions. What is the probability that next summer will be drier than the "average" summer? By how much will global temperature at the end of the century be warmer than the beginning of the century?

Watch this video to learn about the difference between weather and climate. Weather and climate are like the man walking his dog. The dog takes a varied path along the way (like the weather), but the man is setting the long-term direction (like the climate).