Köppen Climate Classification

Köppen Climate Classification

The lecture explains how to read the Köppen climate classification system and use climate graphs to identify the climate of a location.

How the System Was Developed

Köppen classified climates using two kinds of measurable data:

• Average temperature for each month and across the year.
• Average precipitation for each month and across the year.

His interest in botany also influenced the system. Plant distributions helped him check and refine climate boundaries, since plants depend in part on temperature and precipitation.

Climatographs

A climatograph displays a location’s monthly temperature and precipitation:

• The horizontal axis shows the months of the year.
• Precipitation is commonly shown with bars, while temperature is plotted separately.
• The graph shows monthly averages and seasonal patterns, such as wet or dry seasons and changes between winter and summer.

Köppen Letter Codes

First Letter: Major Climate Group

• A — Tropical humid: Warm, wet climates, generally near the equator.
• B — Dry: Climates where evaporation exceeds precipitation; commonly found near 30° north and south.
• C — Mild mid-latitude: Generally mild winters and warm or hot summers.
• D — Severe mid-latitude: Mid-latitude climates with severe, cold winters.
• E — Polar: Very cold climates at high latitudes.
• H — Highland: Mountain climates chiefly controlled by elevation, such as in the Himalayas or Andes. H is an additional category in the modified system discussed in the lecture.

Second Letter: Precipitation Pattern

For A, C, and D climates:

• f: Precipitation throughout the year.
• m: Monsoonal pattern, with a very wet summer.
• w: Dry winter.
• s: Dry summer.

For B climates, the letters are typically capitalized:

• W: Desert; extremely dry.
• S: Steppe; semi-arid.

For E climates, the letters are also capitalized:

• T: Tundra; at least one month has an average temperature above freezing.
• F: Ice cap; every month has an average temperature below freezing.

Third Letter: Additional Temperature Information

Not all climate codes have a third letter.

For C and D climates:

• a: Hot summers.
• b: Warm summers.
• c: Cool summers.
• d: Very cold winters.

For B climates:

• h: Hot desert or steppe.
• k: Cold desert or steppe.

The lecture notes that some deserts, such as those in Mongolia, are colder than warmer deserts like the Sahara because of their more inland location and greater temperature extremes.

How to Use the System

1. Find a location’s climatograph or monthly temperature and precipitation data.
2. Use the broad climate pattern to determine the first-letter group.
3. Use the seasonal precipitation pattern to identify the second letter.
4. If present, use temperature details to determine the third letter.
5. Combine the letters to interpret the location’s climate classification.

Speaker or Source Featured

• Jennifer, the lecturer and presenter, as identified in the video description.