Weather & Climate

What is the Difference? Weather: the daily atmospheric conditions Ex: It’s chilly and cloudy today. Climate: the average weather patterns in a place Ex: This place usually has pretty mild winters.

The 6 factors That Affect Climate Just remember the acronym *LOWER-N* The 6 factors That Affect Climate

1) Latitude Temperature decreases as you approach the poles The further away from the equator you get, the sun’s rays are less direct

2) Ocean Currents The temperature of the ocean affects the temperature of the air that passes over it The warm current off the west coast makes BC warmer there than it should be The cold Labrador current meets the warm Gulf Stream current and makes a lot of fog off of Newfoundland

Ocean Currents

3) Wind and Air Masses Prevailing Winds: winds that blow mostly from a single general direction Westerlies: the prevailing winds in Canada, they blow from west to east That’s why Mississauga gets our weather before we do, and we get it before Oshawa

Air Mass: large amount of air that takes on the climatic conditions of the area where it was formed Polar Front: the boundary between the cold, dry polar air and the warm, wet tropical air

4) Elevation As you climb a mountain, the temperature drops As air rises, it expands and cools As it cools, it will become saturated: it is holding as much vapour as it can at that temperature If the temperature continues to drop, that saturated air won’t be able to hold any more moisture and precipitation will occur

Condensation: when water vapour turns to liquid Dewpoint: the temperature at which air is saturated, anything colder and precipitation will occur

5) Relief As air rises up a mountain, it cools and condenses into precipitation Windward side: the wet, rainy side of the mountain Leeward side: the dry side of the mountain, away from the wind

Windward Side Leeward Side The rainy, lush, green coast of BC The dry interior Okanagan Valley

Rainshadow Effect Rainshadow: a dry area on the leeward side of a mountain range (away from the wind). Where does this happen: the Rockies, the Himalayan, California, the Andes, etc

Rainshadow on Hawaiian mountains Rainshadow on the northern side of the Himalayas

Look at where the deserts are here in South America relative to where the Andes mountains are, and the direction of the wind

6) Near Water Areas that are far from oceans/large lakes have a Continental Climate Areas on the coast have a Maritime Climate

Moderating Effect Water has a Moderating Effect on surrounding areas (it takes away the extremes) Oceans heat up and cool down much more slowly than land In winter, the water retains more of the heat and warms up the surrounding area

Difference Between Climates Continental Climate Maritime Climate Wide range between the coldest and warmest temperatures Less precipitation More precipitation in the summer Generally colder Smaller range between the highest and lowest Lots of precipitation More precipitation in the winter Generally more mild

Climate Map Arctic: cold & dry Subarctic: cold & wet Humid Continental: cool & wet Humid Subtropical: warm & wet Montane: varies with elevation West Coast Marine: cool & wet Steppe/Prairie: cool & semi-dry Mediterranean: warm, has a dry season Tropical: hot, has a dry season Desert: hot & dry

Simplified World Climate Map