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Geography Affects
Climate

Discover how latitude, altitude, and proximity to water shape the climates we experience around the world.

Earth & Space Science

What Is Climate?

Climate is the long-term average of weather conditions in a region, measured over 30 years or more. It includes temperature, precipitation, humidity, and wind patterns. Unlike weather, which changes day to day, climate describes what you expect over time.

Weather vs. Climate

Weather
Short-term atmospheric conditions at a specific time and place. Changes hour to hour, day to day.
Climate
Long-term pattern of weather averaged over 30+ years for a region. Stays relatively stable.

Key Geographic Factors

Latitude
Distance from the equator: determines how directly sunlight hits a region.
Altitude
Height above sea level: higher elevations are cooler.
Water Proximity
Oceans and large lakes moderate temperature swings.

Latitude and Solar Energy

Equator \(0^\circ\)
\(23.5^\circ\)N
\(23.5^\circ\)S
\(66.5^\circ\)N
\(66.5^\circ\)S
 Direct rays Angled rays

The Latitude Rule

1
Low latitudes (\(0^\circ\)\(\text{--}\)\(23.5^\circ\)): tropical climates, warm year-round.
2
Mid latitudes (\(23.5^\circ\)\(\text{--}\)\(66.5^\circ\)): temperate climates, distinct seasons.
3
High latitudes (\(66.5^\circ\)\(\text{--}\)\(90^\circ\)): polar climates, extremely cold.

Altitude and Temperature

Sea level
\(\sim 25^\circ\text{C}\)
 1,000 m
\(\sim 18.5^\circ\text{C}\)
 2,000 m
\(\sim 12^\circ\text{C}\)
 3,000 m
\(\sim 5.5^\circ\text{C}\)
 Summit Altitude increases

Ocean Proximity and Moderation

Coastal City Mild summers Mild winters Small range Inland City Hot summers Cold winters Large range vs.

Climate vs. Weather: Key Distinction

Climate Weather
Timeframe 30+ years Hours to days
Variability Stable patterns Changes rapidly
Example "Tropics are warm" "It's raining now"
Prediction General trends Specific forecasts
Affected by Latitude, altitude, water Air masses, fronts

Other Geographic Factors

Ocean Currents
Warm currents heat nearby coasts. Cold currents cool them. The Gulf Stream warms Western Europe.
Mountain Barriers
Mountains block moist air, creating a rain shadow: one wet side, one dry side.
Vegetation Cover
Forests release moisture and cool the air. Deserts reflect heat and stay extremely hot.

The Rain Shadow Effect

Moist air rises Dry air descends Windward (wet) Leeward (dry) Mountain Peak

How to Analyze a Region's Climate

1
Find the latitude. Is the region near the equator, in the mid-latitudes, or near the poles?
2
Check the altitude. Is the region at sea level, on a plateau, or on a mountain? Apply the lapse rate: \(-6.5\;^\circ\text{C}\) per 1,000 m.
3
Look for nearby water. Is the area coastal or inland? Coastal areas have moderate climates.
4
Identify barriers. Are there mountains blocking wind or moisture? Check for rain shadow effects.
5
Consider ocean currents. Are warm or cold currents flowing nearby? These shift expected temperatures.

Example 1: Quito, Ecuador

Quito sits almost exactly on the equator at latitude \(\sim 0^\circ\text{S}\), but its average temperature is only about \(15\;^\circ\text{C}\). Why is it so cool for a tropical city?

Sea Level
\(\sim 28\;^\circ\text{C}\)
 +2,850 m Quito
\(\sim 15\;^\circ\text{C}\)
\(28 - (2.85 \times 6.5) \approx 28 - 18.5 = 9.5\;^\circ\text{C}\) (actual: \(\sim 15\;^\circ\text{C}\))

Example 2: London vs. Moscow

London and Moscow are at similar latitudes (\(\sim 51^\circ\text{N}\) and \(\sim 55^\circ\text{N}\)), yet London's winter average is about \(5\;^\circ\text{C}\) while Moscow's is \(-10\;^\circ\text{C}\). What explains this?

London Moscow
Latitude \(\sim 51^\circ\text{N}\) \(\sim 55^\circ\text{N}\)
Proximity to ocean Coastal Inland
Ocean current Gulf Stream (warm) None nearby
Winter avg. temp \(\sim 5\;^\circ\text{C}\) \(\sim -10\;^\circ\text{C}\)
Temp. range (annual) Small (\(14^\circ\text{C}\)) Large (\(30^\circ\text{C}\))

Example 3: Seattle vs. Spokane

Both cities are in Washington State at similar latitudes (\(\sim 47^\circ\text{N}\)). Seattle gets about 940 mm of rain per year; Spokane gets only 430 mm. Why?

Seattle Spokane Cascade Range 940 mm/yr 430 mm/yr Pacific moisture

Common Mistakes

✕ Confusing weather with climate
One cold day does not mean the climate is cold. Climate is a 30+ year pattern, not a single event.
✕ Ignoring altitude
Assuming all equatorial regions are hot. Altitude can make tropical locations quite cold.
✕ Forgetting ocean currents
Similar latitudes do not guarantee similar climates. Ocean currents can shift temperatures by \(10\text{--}15\;^\circ\text{C}\).

Question 1 of 5

Which factor is the primary reason the equator is warmer than the poles?

Question 2 of 5

A city at sea level and \(0^\circ\) latitude has an average temperature of about \(28\;^\circ\text{C}\). If a nearby city at the same latitude sits at 2,000 m altitude, what is its approximate temperature?

Question 3 of 5

City A is on the coast. City B is 500 km inland at the same latitude and altitude. Which statement is most likely true?

Question 4 of 5

Which geographic feature best explains why eastern Washington is much drier than western Washington?

Question 5 of 5

London (\(\sim 51^\circ\text{N}\)) has significantly warmer winters than Moscow (\(\sim 55^\circ\text{N}\)). What is the most important geographic reason?