The Weather Notebook: Defining Weather

Defining Weather
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There are a lot of weather terms that people toss about. Sometimes, there is a fine distinction between words with which we thought we were familiar. So todayÐas a public service, of courseÐwe thought it might be helpful to get down to basics, with perhaps the three broadest terms from the weather field: weather, meteorology, and climatology. And here to help us today is New Hampshire State Climatologist Dr. Barry Keim.

Dr. Keim, what's the difference between these terms?

BK: To begin, the weather is what's taking place outside at any given point in time, at some specific location. So, in essence the weather is what you talk about while standing in line at the supermarket. It's either very hot and humid outside or it's cold and windy.

Now meteorology is the short term forecasting of that weather. In other words it tries to interpret the physics of the atmosphere to understand what kind of forces are taking place and how the weather is going to change as a result of those forces.

And long range forecasting usually falls into the domain of the climatologist. Where climatologists look at long term historical trends and patterns and put together, what's the average January temperature. What is the global average temperature and how might those averages change into the future. Climatology can also take on a forecasting component, a predictive type of component when we look at how the averages may change into the future as it relates to say, global warming or something else related to that. But, also climate is a bit more than that in terms of looking at extreme events. In other words, what is the probability of getting seven or eight class four hurricanes striking the United States shoreline, for example, in a given season.

That was Dr. Barry Keim, N.H. State Climatologist. The Weather Notebook is a production of the Mount Washington Observatory, supported by Subaru, and The National Science Foundation.