7.4: Weather vs. Climate
- Page ID
- 33919
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Climate is the average of the weather for a region over time. There is a common confusion that arises when people use the word climate. Often, even if they think they are discussing climate, the conversation will begin with a discussion of the current weather. It might go something like this:
“It was really hot today! Must be global warming…”
Weather
And, indeed, it might be. However, what they are describing is the weather. Weather is the summation of current atmospheric conditions at any given moment. And, to measure it, we use things like thermometers, barometers, and other devices. This information is collected and is used to develop models that can be used for predictive purposes. From these, you get your 1-10-day forecasts. These forecasts of the weather are entirely based on probabilities. A 20% chance of rain just means that, under current weather conditions (or those predicted), it tends to rain 20% of the time. These conditions are a part of a region’s climate story, but they are still defined as weather. While they use recent historical data, they are intended to describe the condition of the atmosphere at a moment in time…perhaps three days from now.
Climate
Climate, on the other hand, is the average of these daily conditions over time. At its most basic and familiar level, climate can be described based upon seasons. Some places on Earth experience four of them (winter through autumn), others experience two (rainy and dry). These short-term climatic conditions are based upon a large array of variables. These include latitude, topography, proximity to the sea, time of year, and so forth. Looking at changes in climate over the course of the year at a given location on the planet provides a short-term picture unique to that location. Climate can also be described on a global average basis. Under these conditions, we can follow long-term changes in temperature and associated variables (greenhouse gases, ice loss, evapotranspiration, etc.) that provide a broader picture of global climate and how it is changing.
Classification of Climate
We use words like sunny, hot, rainy, cold, freezing, windy, etc. to describe weather on a given day. But how do we describe climate since it is the long-term average of weather? The Koppen-Geiger Climate Classification System is used to define different climate categories. Watch the video from 1:49-3:35 and 5:30-5:46. Note the following:
- what the five climate categories are with brief summaries
- why categories are subdivided
- what the first letter indicates
- what the second letter indicates
- what the third letter indicates