Macroclimate – climate of a large (macro) scale region, such as Sahara (hot and dry)
Mesoclimate – climate of “medium” (meso) scale region, such as coastal southern
California (sunny and warm, with dry summers and wet winters)
Microclimate – climate of a small (micro) scale region, such as the climate on the slopes
of a single hill
Heat Island effect – human impact on microclimates due to influence of urban areas
C - Mesothermal (mesos – middle)
Moderate Temperature, seasonality (distinct summer and winter)
summers long and mild winters
Annual precipitation greater than annual potential evapotranspiration
Mediterranean Climate (Csa,Csb)
Csa (s – dry summer, a – hot summer)
Csb (s – dry summer, b – mild summer)
Generally found on west coasts at 300 to 400 latitude
Subtropical high pressure in summer and westerly wind movement in winter
Leads to warm dry summer and mild moist winter
Vegetation green winter and yellow summer
Chaparral – low, scrubby bushes that grow together in a thick tangle
Csb further inland – more continental influence
Humid Subtropical Climate – Cfa
f – always moist, a – hot summer
Extends inland from continental east coasts between 150 to 200 and 400 latitude
Summers hot and humid – frequent convective showers
Winters influenced by cyclonic systems
Thus mild winters and hot summers
Vegetation – wetter portions forests of broad-leaf deciduous trees, pine forests on sandy
soils and mixed forests
Vegetation in drier interiors – grasslands
Marine West Coast Climate - Cfb, Cfc
f – always moist, b – mild summer, c – cool summer
Close to sea and prevailing onshore winds make climate one of most temperate in the
world
Found between 400 and 650 latitude (midlatitude) in regions that are continuously
influenced by the westerlies, receive ample precipitation throughout the year
Annual variation in temperature is relatively small due to marine influence (marine
influence more important that latitude in determining temperature)
Climate one of the cloudiest, foggiest, and stormiest in the world, especially in the winter
Amount of precipitation is influenced by local topography
Humid Microthermal Climate Regions
4 seasons - recognizable summer and distinct winter plus spring and fall
Generally located between 350 N and 750 N
Influenced by the westerlies and the storms of the polar front
Little moderating influence of the oceans because of position in the continental interiors
and at high latitudes
Surplus of precipitation over potential evapotranspiration
Humid Microthermal Climate Regions (continued)
Year around rainfall
Maritime tropical air masses in summer and continental polar air masses in winter
Monsoon effect and strong summer convection combine to produce precipitation
maximum in the summer
Regions experience significant snow cover with unpredictable and variable nature of
weather
Humid Continental, Hot Summer Climate (Dfa, Dwa)
f – always moist, a – hot summer
w – dry winter, a – hot summer
Relatively limited in its distribution on the Eurasian landmass
In the United States distributed over a wide area
Great agricultural potential – length of growing season directly related to latitude
Continental interiors range in temperature large
Total precipitation decreases both poleward and inland
Summer long, humid and hot and winters have snow
Humid Continental, Mild Summer Climate ( Dfb, Dwb)
f – always moist, b – mild summer
w – dry winter, b – mild summer
Mild summer climate lies poleward from the hot summer climate
Distinct seasonality and significant climatic variation in precipitation from place to place
in the climate region
Because region more towards the pole less precipitation
Monsoon effect in Asia produces a dry winter season
Summers are shorter and not as hot and winters are more severe, longer and colder
(compared to Dfa and Dwa)
Growing season shorter and less precipitation
Subarctic Climate ( Dfc, Dwc, Dfd, Dwd)
f – always moist, w – dry winter, c – cool summer, d – cold winter
Furthest poleward and most extreme of microthermal climates
Poleward boundary of subarctic climate is poleward limit of forest growth
Most severe winter subtypes (Dfd and Dwd) along poleward margins or deep in the
interior of the landmass
Subtypes with winter drought (Dwc and Dwd) are associated with Siberian High over
interior Asia during winter
Short cool summers and long (8 months), bitterly cold winters ( not much time for spring
and fall) - because of high latitude summer days are long and nights short - subarctic has
largest annual temperature ranges of any climate due to intense heating and cooling of
land
Subarctic precipitation influences by continentality and latitude – lower annual
precipitation
Polar Climatic Regions ( ET and EF)
ET Tundra – warm season chilly and damp, permafrost can melt in spots and get
marshes, swamps and bogs ( black flies, mosquitoes and gnats)
Winters cold and long, precipitation is generally low
EF Ice-Cap - most severe and restrictive climate on earth
Antarctica coldest place in the world ( -1270 F) – receives little or no insolation - also
Greenland and Antarctica have regions over 10,000 feet in elevation
Little precipitation in polar climates
Highland Climatic Regions
Controls of highland climate – elevation, exposure
Exposure – winds ( windward or lee) – insolation (slope aspect - slopes facing the
equator get direct rays of the sun or facing poleward are in shadow; west facing get
afternoon sun or east facing get morning sun)
Highland climates are cool, moist islands in the midst of the zonal climates around them
Changeable weather from hour to hour
Tree line – low winter temperatures and severe wind stress eliminate all forms of
vegetation except those that grow low to the ground
Snow line – summer melting is insufficient to remove all of the preceding winter’s
snowfall