Weather & Climate – Chapter 31 Notes &
Directions: First read Chapter 31 in
your Earth Science textbook.
Weather is the temporary conditions in an area; climate is
an average of the weather conditions taken over a long period of time,
usually at least 30 years. Weather is helpful in determining how you
should dress today, or which clothes you will pack for a vacation, but
climate is helpful for determining whether or not to build (or invest
money, or plant) in an area. In other words, knowing that the average
temperature in MO is 59 degrees (over a 30 year period) won’t help you
get dressed tomorrow, but might help you pick a tree or some flowering
perennials for your yard.
Six main factors
affect the climate in your area.
Latitude – The closer to the Arctic and Antarctic Circle
you get, the colder and dryer it is.The closer to the Equator,
the hotter and more humid it is.|
Altitude – The higher above sea level you get, the colder and
dryer it is.|
Prevailing Winds – The windward edge of an island or continent
will be much more humid than the leeward side.|
Topography – (especially when combined with the prevailing
winds) If mountains are present, the windward side is much
more humid, since the air masses are cooled and condensed as
they rise to go over the mountains. The mass will drop much of its
moisture before crossing over. The air mass sucks up
moisture as it warms and expands during its descent on the
leeward side of the mountains, frequently creating desert
Distance from Large Bodies of Water – Water has “high
specific heat”, which means it heats up slowly and cools
off slowly. Seattle is much farther north than we are, but
year round, it seldom gets above 70 or below 40 degrees.
Large bodies of water “moderate” temperatures.|
Nearby Ocean Currents – A permanent current of ocean
water that is warmer or colder than the local conditions
are will have an effect on the local climate. There are
palm trees growing on the coast of Ireland, much farther
north than we are, due to the Gulf Stream.|
Do the 17 Review Questions and 2 Critical Thinking
Questions on pp. 592 – 593.