Climate Regions and Influencing Factors
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Weather: the condition of the bottom layer of
the earth’s atmosphere over a short time period
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Includes temp., precipitation, and wind
Climate: the weather pattern an area typically
experiences over a long time period
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“Climate is what you expect; weather is what you get”
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Relationship to the sun
Latitude
Wind & ocean currents
Precipitation
Water bodies & landforms
Elevation
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Sun = major source of climates
Greenhouse effect
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Small amount of sun’s radiation reaches earth
Atmosphere traps heat, allowing organisms to grow
Rotation: spin of the earth on its axis (24 hrs)
Revolution: complete orbit around the sun
(365 ¼ days)
Tilt = 23 ½ degrees
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Area between Tropic of Cancer (23.5°N) & Tropic of
Capricorn (23.5°S) receives the most direct sunlight
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Seasons
North Pole tilted in towards the sun = summer in the
Northern hemisphere
 More direct sunlight to that hemisphere
 Longer, warmer days
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Summer solstice (June 21) & winter solstice
(December 21) mark the change of season
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Sun is directly overhead at T. of Cancer & Capricorn
Vernal & autumnal equinoxes (March 21 &
September 23)
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Sun is directly overhead at the Equator
Length of day & night are near equal
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Because of tilt & path of sun’s rays, latitude
impacts climate
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How far a place is from the Equator dictates temp.
Low latitudes (0-23.5°N, 0-23.5°S)
“Tropics”; hot year-round
 Ex: Sierra Leon (Africa)
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Middle latitudes (23.5-66.5°N, 23.5-66.5°S)
“Temperate”; cooler than tropics, wide variety of temps
 Ex: Pennsylvania (U.S.)
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High latitudes (66.5°N-N.pole, 66.5°S-S.pole)
“Polar”; consistently cold; mostly indirect sunlight
 Ex: Northwest Terr. (Canada)
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Sun’s heat distributed by convection
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Heat rises, creates circular motion
Air & water moves in this way: air = wind, water =
currents
Wind
Warm air rises (low pressure zones) & moves
towards the poles; cool air sinks (high pressure
zones) & moves towards the Equator
 *Winds are named for the direction of origin (i.e.
“westerlies” come from the west)
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Ocean currents
Follow similar pattern as wind
 Cold water moves poles  Equator; warm water
moves Equator  poles
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Precipitation = all forms of water that fall from
the atmosphere
Timing & volume  climate type
Warm air absorbs moisture; when it cools,
excess moisture condenses into liquid  clouds
 precipitation
3 types: convectional, orographic, frontal
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Convectional
Air rises because it is hot & humid  cooling 
precipitation
 Common in tropical climates near the Equator
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Orographic
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Air rises because it is forced up over high landforms
 cooling  precipitation
Common in coastal areas
Creates windward & leeward sides of mtn ranges
Frontal
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Air rises because it meets a front of cooler air that
pushes it up  cooling  precipitation
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Coastal & inland mountains
Deserts
Forests
Even tall buildings
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All can change air flow, precip. patterns, & climate
Water bodies
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Wind that crosses water takes on its temperature 
milder climates in nearby land areas
Temp. is changed by warm or cool air & water
currents
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Stronger determinant of climate than latitude
in places with very high elevation
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Ex: Mt. Kilimanjaro in Tanzania (4°S, >19,000 ft)
Air temp. decreases ~3.5° per 1,000 ft of
elevation