The difference between climate and weather

The distinction has often been made intuitively. For example this quote from Robert Heinlein “Climate is what you expect; weather is what you get”. This makes sense; we know that winter is colder than summer, and that the UK has a terrible climate.

From this we can draw the following relatively simple definition for weather.

Weather is the here and now; it is the current state of the atmosphere. Is it raining? Is it windy? Weather varies on timescales of minutes to days. Storms, rainbows and sunny days are all examples of weather.

Climate is a bit harder to nail down. We speak of one summer being particularly warm. This suggests that our notion of climate is based on more than a single year’s weather. The exact length of time for climate is unhelpfully fuzzy, but a working definition would be:

Climate is the long-term average of the weather for a particular location and time of year.

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