After days of extreme cold, like the ones we experienced early last week, I often notice comments on social media sites such as “So much for global warming”. These comments seem to confuse long-term, global phenomena with short-term, regional weather events. I think some of the confusion people have about this topic comes from our understanding of the different terminology used to describe specific events and phenomena. One set of terminology that can be confusing is the difference between weather and climate.
What we all experience on a day-to-day basis is the weather. Weather refers to short-term conditions occurring on time scales defined by minutes, days or weeks. It’s what’s going on outside on a particular day, including factors such as temperature, humidity, precipitation and wind. If you are asking questions like “How hot is it?”, “Is it snowing?”, or “What’s the humidity?” – you are asking about the weather.
Climate is different. Climate is the long-term average of weather trends and cycles over time, occurring on time scales defined by decades and centuries. Those who know the climate in Ohio know that we have four distinct seasons, one of which is a cold, snowy winter. Climate is a range of expected conditions over a long period of time, while weather is a specific condition at a specific time.
An easy way to remember these terms is the saying, “Climate is what you expect; weather is what you get.” We expect that summer in Ohio will be warm and humid, but it’s entirely possible that we’ll get some cooler days with lower humidity. Similarly, we expect that winter will be cold, but exactly how cold it will be on any given day will vary.
The important thing to remember as we all bemoan the unusually low temperatures is that it takes much more than a couple of very cold days to prove or disprove a climate trend.
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