Köppen Classification System

The major first letters are:

Note: A highland (mountain) climate is also a part of this system which is part of this classification model.

B DESERT TYPE CLIMATES

Step 1 DETERMINING WHETHER THE CLIMATE IS A ARID B TYPE CLIMATE.
To determine if the climate is a B (first letter) arid (desert) type climate you need to consult the appropriate graph. The graph that you use is determined by the concentration of the precipitation at the station.

NOTE: These graphs will help you determine if the climate is a B climate or not based on mean annual temperatures and precipitation. YOU WILL NEED TO KNOW THE ANNUAL TEMPERATURES and PRECIPITATION to see where the point lies within the graph.

These graphs also help you determine the SECOND letter for B type climates. Note: you chose a preliminary second letter already, but THIS WILL NOT BE USED if this is a B climate.

ALSO NOTE: These graphs will help you determine the FIRST LETTER of a climate that is NOT a B CLIMATE. In other words, if you determine this is not a B type climate, in this step you will be able to determine a field of letters that your climate might be associated with. These first letters include: ACD or E type climates. Now choose the correct graph below and determine if the climate is a B or some other type climate.

CONSIDER THESE CONDITIONS:

IF the precipitation is concentrated in SUMMER, then the climate is a DRY WINTER type climate and the SECOND LETTER WILL BE a small "w" tap here for the w graph.

IF the precipitation is concentrated in WINTER,then the climate is a DRY SUMMER type climate and the SECOND LETTER WILL BE a small "s".tap here for the s graph.

IF there is NO CONCENTRATION in either winter or summer, then the SECOND LETTER WILL BE a small "f"
tap here for the f graph.