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A muchness of Koppen-bickering of late has made me think: how would you classify climates if given the chance to start at the drawing board again?
( Given most of us aren't metereologists, this is all in good fun. )
Here would be my take:
Average Annual Temperature
Seaasonal Temperature Variability
Total Percipitation
Seasonal Percipitation Variation
Percipitation Distribution
I'd use letter classifications for all of these, but simplify it:
AVERAGE ANNUAL TEMPERATURE
A: Climates with an average of -10C or lower.
B: Climates with an average between -10 and 0C.
C: Climates with an average between 0 and 10C.
D: Climates with an average between 10 and 20C.
E: Climates with an average between 20 and 30C.
F: Climates with an average of 30C or higher.
AVERAGE SEASONAL VARIANCE.
A: Climates with a seasonal variance of 5C or less.
B: Climates with a seaonal variance of 5-10C.
C: Climates with a seasonal variance of 10-15C.
D: Climates with a seasonal variance of 15-25C.
E: Climates with a seasonal variance of 25-35C.
F: Climates with a seasonal variance of 35C or more.
AVERAGE ANNUAL PERCIPITATION
A: Climates with less than 150MM.
B: Climates with 150-300MM.
C: Climates with 300-600MM.
D: Climates with 600-1200MM.
E: Climates with 1200-2000MM.
F: Climates with 2000MM or more.
AVERAGE PERCIPITATION VARIANCE
A: Climates with less than a 10% variance between the wettest and driest months.
B: Climates with a 10% to 25% variance between the wettest and driest months.
C: Climates with a 25% to 50% variance between the wettest and driest months.
D: Climates with a 50% to 75% variance between the wettest and driest months.
E: Climates with a 50% to 99% variance between the wettest and driest months.
F: Climates with a 99% or more variance between the wettest and driest months.
PERCIPITATION DISTRIBUTION
A: No predominant wet or dry season.
B: Bimodal, multiple distinct wet and dry seasons.
C: Hemispheric winter maximum.
D: Hemispheric spring maximum.
E: Hemispheric summer maximum.
F: Hemispheric autumn maximum.
So, for example, my current climate would look like:
Haven't really thought one out much but I would elevate the categories of temperate, subtropical etc.. to much higher temperatures ranges than the current ones.
For example:
Mean Temperatures
A = Tropical: 25°C or higher
B= Subtropical: 17-24°C
C = Temperate: 12 - 16°C
D = Cool: 7 - 11°C
E = Subarctic: >7°C
Then based on temperature range we'd have "continental" (C), "maritime" (M) designations, and based on rainfall quantity would have a number for each category of rainfall quantities as follows:
Ah, awesome thread. I've been thinking about my own climate classification for a while indeed !
In your classification, my current climate, i.e.
Nice is : D C D E F
while
my ideal climate would be : E A D F F
For my own classification, this is how I would proceed :
First letter for winter temp
A for hot winters (>24°C) -
B for warm winters (18 to 24°C)
C for mild winters (12 to 18°C)
D for cool winters (6 to 12°C)
E for chilly winters (0 to 6°C)
F for freezing winters (-10°C to 0°C)
G for frigid winters (below -10°C)
Second letter for summer :
A for scorching summers (>30°C)
B for hot summers (>26°C)
C for warm summers (>22°C)
D for lukewarm summers (>18°C)
E for cool summers (>14°C)
F for cold summers (>10°C)
G for nonexistent summers (<10°C)
Third letter for precipitation :
no letter if all months average between 30mm and 200mm
w if a winter month has less than 30mm
s if a summer month has less than 30mm
if both summer and winter have months below 30mm, s if summer overall drier, w if winter overall drier
d if all months have less than 30mm
summer being 6 month period with longest days
Add :
+ if one month has more than 300mm
++ is one month has more than 600mm
Examples :
Nice = DCs
Paris = ED
Hong Kong = CBw+
Sydney = CC
Fairbanks = GEw
Death Valley = DAd
Singapore = AB+
Reykjavik = FF
South Pole = GGd
Mumbai = BBw++
I don't have a climate classification system per se. Rather I have a rating system, with the grades A, B, C, D, E, and F (sound familiar? ), based on my own preferences. This has been revised over the last few months to encompass just about any climate that may exist. The A-grade criteria is a baseline, and the other classification is a hierarchy based on where the other climates fall short. Here it is:
Quote:
A-Grade climates:
Summers
- Hottest month highs average sub-80, lows average sub-60
- No more than 3 months' highs average 70+, lows 50+
- Hottest month daily mean must be above freezing
- If hottest month highs sub-70, lows sub-50, A+ grade given to climates that meet the other criteria
Winters
- At least 2 but not more than 3 months’ highs average 25 or lower
- Note: Note: an exception to the above criterion’s maximum length is if the hottest month highs average sub-70 and the lows sub-50; if true, then any A+ grade is reduced to a regular A grade
- 3 coldest months' daily means 26.6 or below
- Record high for coldest month sub-50, other 2 of the 3 coldest months' record highs sub-60 (assuming record highs are available, if not then this section does not apply)
- If the above criterion is not met, then the A- grade is given
- Coldest month daily mean must be -10 or higher
B-Grade climates:
1. B-grade is given to climates that fail to meet the A-grade Winter criteria due to cold (be it too cold or too long), but still have a coldest month mean above -36.
2. B-grade is also given to climates that fail to meet the A-grade Winter criteria for being too warm. These climates must have, for each of the three coldest months, average highs sub-40 and lows freezing or subfreezing. In addition, they must have the hottest month average highs sub-70 and lows sub-50.
C-Grade climates:
1. C-grade is given to climates that fail to meet the second set of B-grade criteria due to their Winters being too warm. These climates must also have the hottest month highs average sub-70.
2. C-grade is also given to climates that fail to meet the Summer criteria due to having hottest month means below freezing, and/or have coldest month means of -36 or below.
3. C-grade is also given to climates that fail to meet the Summer criterion of the second set of B-grade criteria due to being too warm (70+ highs or 50+ lows in the hottest month). These climates must otherwise meet all of the B-grade criteria.
D-Grade Climates:
1. D-grade is given to climates that have the coldest month highs average sub-40 and lows average freezing or subfreezing, but fail the Summer criteria of A-grade, either the hottest months’ highs averaging 80+ and lows 60+, or highs and lows averaging 70+/50+ for more than 3 months. No month may have average a high of 90 or higher, or a low of 70 or higher.
E-Grade Climates:
1. E-grade is given to climates that otherwise meet the criteria of D-grade, but are too warm in the Winter or too hot in the Summer. These climates must have the coldest month’s high be sub-50, and have a month that on average receives at least one inch of snowfall. The hottest month may have an average high of 90+, but average lows must stay sub-70.
2. An E-grade is also given to climates that do not meet the sub-50 Winter high criterion, but have nights in the coldest month average sub-20. Winter highs must still be sub-60, and in addition, the hottest month must average sub-55 lows. If the climate averages less than 30 inches of snow per year, or the snowfall is unknown, this grade is reduced to E minus.
F-Grade Climates:
1. F-grade is given to climates that fail to meet the criteria of the A, B, C, D, or E grades. This includes the hot-summer subtropics and tropics.
2. In addition, the F- grade is given to otherwise F-grade climates that have a hottest month average low of 75 or greater, and that have 10 degrees or less difference between the means of the hottest and coldest months
Also note that this rating system is not hard and fast. I may (and often do) rate climates differently than this based on other factors, but this is a good guideline and enables quick application as well as cataloging. It would be interesting to construct a world map of climates based on this.
…finally a thread that doesn’t revolve around cold vs warm…lol.
One of the things I think we forget is that the climatologists who framed the climate classifications not only tried to link climates based on their thermal similarities…but also of their genetic similarities. I spent a modest amount of time studying climatology in college and had a number of different professors from different parts of the world. They all had different ideas on where the rough climate boundaries should be – yet they all strongly agreed that grouping climates based on their genetics or causative factors (e.g., prevailing air masses, wind zones ) is the bases for good climate classification. This is why even when Koppen collected climate data back in the 1880’s – he tried to understand the genetics of what makes one climate group different from another. The problem was he lacked the data. When Trewartha regrouped climates in the 1960’s – he had many more tools at his disposal (and much more data!)
Attempting to group climates by thermal boundaries “only” can lead to an unrealistic image of many climates. Take the concept of using annual mean temperatures: San Francisco, California and Richmond, Virginia have the same annual mean temperature and one might assume that annually their climates are close to the same. Yet, as anyone knows who has lived in both cities knows they are very different climates. The same mean annual temp for both cities hides a lot about both climates...like that winter lows average 15 F warmer in oceanic San Francisco…or that for 7 months a year the average daily high in Richmond is 70 F/21 C or higher, yet only 4 months in San Francisco has average highs of 70 F or higher….in San Francisco one often needs a light jacket in summer – in Richmond one often needs Bermuda shorts and a t-shirt in summer – lol. Good climate classification (like the Trewartha system) places these two cities into very different climate groups with far different seasonal climate controls, even though they have the same exact annual mean temperature.
So I think that it is quite difficult to construct a reasonable climate classification system based mostly on temperatures - weather annual, seasonal, hottest/coldest months, …etc. IMO, Good climate classification starts and ends with genetic grouping.
I don't have a climate classification system per se. Rather I have a rating system, with the grades A, B, C, D, E, and F (sound familiar? ), based on my own preferences. This has been revised over the last few months to encompass just about any climate that may exist. The A-grade criteria is a baseline, and the other classification is a hierarchy based on where the other climates fall short. Here it is:
Also note that this rating system is not hard and fast. I may (and often do) rate climates differently than this based on other factors, but this is a good guideline and enables quick application as well as cataloging. It would be interesting to construct a world map of climates based on this.
I like more than one alternate I've seen here on CD.com, and most improve on Koppen, etc. My system isn't lettered or numbered, and barely mapped for part of the US. But it's simple, consistent, and seems to reflect nature or gardens, too -
- oceanic or continental influence, W to E coasts (includes atmospheric humidity, clouds)
- temperature (averages, durations, extremes)
- precipitation (averages, season/s of precipitation)
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)
Warning: Long, complex post
), based on my own preferences. This has been revised over the last few months to encompass just about any climate that may exist. The A-grade criteria is a baseline, and the other classification is a hierarchy based on where the other climates fall short. Here it is:
