Brauner Climate Classification

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The The Brauner Climate Classification, is a system of climate classification, developed by Kivuian climatologist Stefan Brauner (1852-1931) in 1892, with modifications made in 1916.

The Brauner Climate Classification system divides climates into five main groups, based on patterns of seasonal precipitation and temperature. The five main groups are A (tropical), B (arid), C (temperate), D (continental), and E (polar). A letter is used to designated to each group and subgroup. All climates are assigned a main group (the first letter). All climates, with an exception of those in the E group, are assigned a seasonal precipitation subgroup (the second letter). For example, Am indicates a tropical monsoon climate. A temperature subgroup is given to the B, C, and D groups. The system assigns a third subgroup based on temperature for all groups other than those in the A group, indicated by the third letter for climates in B, C, D, and the second letter for climates in E. For example, Csa indicates a X climate with warm summers as indicated by the ending b. Climates are classified based on specific criteria unique to each climate type.

Climate Groups

Group A: tropical climates

This type of climate has an average temperature of 18 °C (64.4 °F) or higher every month of the year, with significant precipitation.

• Af = Tropical rainforest climate; average precipitation of at least 60 mm (2.4 in) in every month.

• Am = Tropical monsoon climate; driest month (which nearly always occurs at or soon after the "winter" solstice for that side of the equator) with precipitation less than 60 mm (2.4 in), but at least 100 minus the total annual precipation in millimeters divided by 25.

• Aw and As = Tropical wet and dry or savanna climate; with the driest month having precipitation less than 60 mm (2.4 in) and less than 100 minus the total annual precipation in millimeters divided by 25.

Group B: arid climates

This type of climate is defined by little precipitation that does not fit the polar (EF or ET) criteria of no month with an average temperature greater than 10 °C (50 °F).

The threshold in millimeters is determined by multiplying the average annual temperature in Celsius by 20, then adding:

• • (a) 280 if 70% or more of the total precipitation is in the spring and summer months (April–September in the Northern Hemisphere, or October–March in the Southern), or
  • (b) 140 if 30%–70% of the total precipitation is received during the spring and summer, or
  • (c) 0 if less than 30% of the total precipitation is received during the spring and summer.

If the annual precipitation is less than 50% of this threshold, the classification is BW (arid: desert climate); if it is in the range of 50%–100% of the threshold, the classification is BS (semi-arid: steppe climate).

A third letter can be included to indicate temperature. Brauner used h to mean the coldest month that has an average temperature above 0 °C (32 °F) (or −3 °C (27 °F)), with k denoting that at least one month's averages below 0 °C (or −3 °C (27 °F)).

• BWh = Hot desert climate
• BWk = Cold desert climate
• BSh = Hot semi-arid climate
• BSk = Cold semi-arid climate

Group C: temperate climates

This type of climate has the coldest month averaging between 0 °C (32 °F) (or −3 °C (27 °F) and 18 °C (64.4 °F) and at least one month averaging above 10 °C (50 °F).For the distribution of precipitation in locations that both satisfy a dry summer (Cs) and a dry winter (Cw), a location is considered to have a wet summer (Cw) when more precipitation falls within the summer months than the winter months while a location is considered to have a dry summer (Cs) when more precipitation falls within the winter months.

• Cfa = Humid subtropical climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), at least one month's average temperature above 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled). No dry months in the summer.
• Cfb = Temperate oceanic climate or subtropical highland climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Cfc = Subpolar oceanic climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Cwa = Monsoon-influenced humid subtropical climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), at least one month's average temperature above 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Cwb = Subtropical highland climate or Monsoon-influenced temperate oceanic climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (an alternative definition is 70% or more of average annual precipitation received in the warmest six months).
• Cwc = Cold subtropical highland climate or Monsoon-influenced subpolar oceanic climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Csa = Caelean-influenced Hot-summer climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), at least one month's average temperature above 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 40 mm (1.6 in).
• Csb = Caelean-influenced Warm-summer climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 40 mm (1.6 in).
• Csc = Caelean-influenced Cold-summer climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 40 mm (1.6 in).

Group D: continental climates

This type of climate has at least one month averaging below 0 °C (32 °F) (or −3 °C (27 °F)) and at least one month averaging above 10 °C (50 °F).

• Dfa = Hot-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), at least one month's average temperature above 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Dfb = Warm-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Dfc = Subarctic climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Dfd = Extremely cold subarctic climate; coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither the abovementioned set of conditions fulfilled).
• Dwa = Monsoon-influenced hot-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), at least one month's average temperature above 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Dwb = Monsoon-influenced warm-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Dwc = Monsoon-influenced subarctic climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Dwd = Monsoon-influenced extremely cold subarctic climate; coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
• Dsa = Caelean-influenced Hot-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), average temperature of the warmest month above 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 30 mm (1.2 in).
• Dsb = Caelean-influenced Warm-summer humid continental climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)), average temperature of the warmest month below 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 30 mm (1.2 in).
• Dsc = Caelean-influenced Warm-summer subarctic climate; coldest month averaging below 0 °C (32 °F) (or −3 °C (27 °F)) and 1–3 months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 30 mm (1.2 in).
• Dsd = Caelean-influenced extremely cold subarctic climate; coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and the driest month of summer receives less than 30 mm (1.2 in).

Group E: polar and alpine climates

This type of climate has every month of the year with an average temperature below 10 °C (50 °F).

• ET = Tundra climate; average temperature of warmest month between 0 °C (32 °F) and 10 °C (50 °F).[1][10]
• EF = Ice cap climate; eternal winter, with all 12 months of the year with average temperatures below 0 °C (32 °F).

Mapping

Brauner also developed a color code for his classification system to be used on maps.

Group A: Tropical climates

•   Tropical Rainforest (Af)
•   Tropical Monsoon (Am)
•   Tropical Savannah (Aw)
•   Tropical Savannah (As)

Group B: Arid climates

•    Hot desert climate (BWh)
•    Cold desert climate (BWk)
•    Hot semi-arid climate (BSh)
•    Cold semi-arid climate (BSk)

Group C: Temperate climates

•    Humid Subtropical Climate (Cfa)
•    Oceanic Climate (Cfb)
•    Subpolar Oceanic Climate (Cfc)

•    Hot-summer Caelean Climate (Csa)
•    Warm-summer Caelean Climate (Csb)
•    Cold-summer Caelean Climate (Csc)

•    Monsoon-influenced Humid Suptropical Climate (Cwa)
•    Subtropical Highland Climate (Cwb)
•    Cold Subtropical Highland Climate (Cwc)

Group D: Continental climates

•    Hot-summer Humid Continental Climate (Dfa)
•    Warm-summer Humid Continental Climate (Dfb)
•    Subartic Climate (Dfc)
•    Extremely Cold Subarctic Climate (Dfd)

•    Caelean-influenced Hot-summer Humid Continental Climate (Dsa)
•    Caelean-influenced Warm-summer Humid Continental Climate (Dsb)
•    Caelean-influenced Subarctic Climate (Dsc)
•    Caelean-influenced Extremely Cold Subarctic Climate (Dsd)

•    Monsoon-influenced Hot-summer Humid Continental Climate (Dwa)
•    Monsoon-influenced Warm-summer Humid Continental Climate (Dwb)
•    Monsoon-influenced Subarctic Climate (Dwc)
•   Monsoon-influenced Extremely Cold Subarctic Climate (Dwd)

Group E: Polar and Alpine climates

•    Tundra Climate (ET)
•    Ice Cap Climate (EF)