TREWARTHA’S CLIMATIC CLASSIFICATION
The Trewartha’s climatic classification is a climatic classification first published
by an American Geographer “Glenn Thomas Trewartha” in 1966 and was
considered as the modified version of the Koeppen’s System.
Trewartha’s basic aim was to present a simple and generalized scheme, so that
the major type of the world climates would be easily and realistically which
was identified and cartographically represented on world map.
He made the use of two most important and basic weather elements i.e.
temperature and precipitation as the basic for his own classification.
He has classified world climates in seven climatic groups.
Out of which Six A, C, D, E, F and H are based on temperature criteria.
Group A: Tropical Climates
Group C: Sub tropical climates
Group D: Temperate and Continental Climates
Group E: Sub Artic climate
Group F: Polar climate
Group H: Highlands Climates
And the Seventh “B” --- in the dry group based on precipitation.
Group B: Dry [arid and Semiarid] climates.
Climatic Group Based on Temperature Criteria.
Group A: This is the tropical climate group and found in the low latitudes on
Each side of the equator.
1. No winter seasons
2. Temperature is uniform throughout the year with moderate
rainfall.
a. Ar: It is a tropical wet climate characteristics by less than 2 dry months.
b. Aw: It is aa tropical wet and dry climate; 2 months are usually dry.
The Trewartha’s climatic classification is a climatic classification first published
by an American Geographer “Glenn Thomas Trewartha” in 1966 and was
considered as the modified version of the Koeppen’s System.
Trewartha’s basic aim was to present a simple and generalized scheme, so that
the major type of the world climates would be easily and realistically which
was identified and cartographically represented on world map.
He made the use of two most important and basic weather elements i.e.
temperature and precipitation as the basic for his own classification.
He has classified world climates in seven climatic groups.
Out of which Six A, C, D, E, F and H are based on temperature criteria.
Group A: Tropical Climates
Group C: Sub tropical climates
Group D: Temperate and Continental Climates
Group E: Sub Artic climate
Group F: Polar climate
Group H: Highlands Climates
And the Seventh “B” --- in the dry group based on precipitation.
Group B: Dry [arid and Semiarid] climates.
Climatic Group Based on Temperature Criteria.
Group A: This is the tropical climate group and found in the low latitudes on
Each side of the equator.
1. No winter seasons
2. Temperature is uniform throughout the year with moderate
rainfall.
a. Ar: It is a tropical wet climate characteristics by less than 2 dry months.
b. Aw: It is aa tropical wet and dry climate; 2 months are usually dry.
