Two characteristics of Climate that are most important: 1) The average temperature over the year 2) The annual temperature range (difference between the average temperature of the hottest month and the average temperature of the coldest month)

 Arid or Dry = a region in which the average total precipitation during the year is less than the average yearly potential evapotranspiration (evaporation and transpiration)  Humid or Wet = an area that has an average precipitation for the year is greater than the average potential evapotranspiration  Deserts = regions where the potential evapotranspiration is much greater than the precipitation  Sub-Arid or Sub-Humid = an area that has equal amounts of precipitation and potential evapotranspiration

Latitude has an influence on both temperature and moisture At low latitudes, there is very little temperature variation because the angle of insolation is always high At high latitudes, the temperatures are low because the angle of insolation is never large

♦Moisture condition vary with latitudes because of the location of the planetary wind and moisture belts (ESRT – pg 14) ♦Where there is a low pressure, air rises – the cooling of this air creates clouds and precipitation (humid climates) ♦Where there is a high pressure, air sinks – the air warms creating a dry or arid climate **The combo if Latitude and Moisture creates a latitudinal climate pattern**

 If land mass is near a large body of water, its temperatures will be moderated by the slow heating and cooling off of the water  An area that is moderated by a body of water is said to have a maritime climate Ex: Long Island  Maritime climates have cooler summers and warmer winters  Inland areas away from water are called continental climates Ex: Central North America  Continental climates have warmer summers and cooler winters

o Prevailing winds are caused by air pressure differences (from unequal heating of the Earth by the sun) and the effects of Earth’s rotation o Most of the United States is located in the prevailing southwesterly wind belt for much of the year o This allows most of the weather conditions to move from the southwest to the northeast o The west coast of the US has more of a maritime climate than the east coast because the west coast’s winds are from the ocean

Currents flowing away from the equator carry warm water to higher latitudes, while currents flowing toward the equator carry cool water to lower latitudes A cool ocean current will cause a coastal area to have cooler temperatures and less precipitation A warm ocean current will cause a coastal are to have warmer temperatures and more precipitation ***ESRT pg. 4 : Surface Currents***

 The higher the altitude at and given latitude, the cooler the climate --because air rises, expands and cools  Areas at higher altitudes generally have more precipitation than lower areas

Mountains that intersect prevailing winds and force the winds up the mountain. The side of the mountain in which the prevailing winds blow up, is called the windward side. As the prevailing wind travels up the side of the mountain, it expands and cools. When it cools to its dew point, condensation occurs which forms clouds and precipitation. As a result the windward side is cooler and more humid. The opposite side of the mountain in which the winds descend is called the leeward side. As the air descends it is compressed and warmed. As a result, the leeward side is warmer and drier.

Arid Climate = has desert vegetation Hot/Humid Climate = has a tropical rainforest **When rainforests are cut down (deforestation), and converted into farms or grazing land, the climate often becomes hotter and less humid.**

Without clouds = the atmosphere is more transparent and more of the sun’s energy can reach and heat Earth’s surface With clouds = the sun’s rays are absorbed or reflected back into space **Although the equator is seems hot, they have many thunderstorms which produce large clouds. Deserts on the other hand, rarely have clouds, allowing temperatures to be high**