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Would you classify on the basis of the 0 C (freeze) or -3 C (continuous snow) winter isotherms?
-3 C
Not that -3C really guarantees continuous snow in North America. Winters are very changeable and fickle here. One week it could be brutally cold, another highs in the 50's.
But at least there is a decent chance that there will be a stretch of time (maybe a couple weeks) that temps won't rise above freezing.
Obviously it doesn't apply to maritime climates. A maritime climate that has snow on the ground is subarctic.
But I equate a "classical" temperate continental climate with "4 seasons". And a true 4 season climate should have a real winter. I think the southern portion of the Great Lakes region exemplifies what a 4 season climate should be like. In other words places like Chicago, Cleveland, Detroit. Outside of the Great Lakes, probably Des Moines, Iowa, Albany, NY or Hartford, CT.
But how about a "real summer"?
In my opinion, Toronto lacks a consistent "real" summer most years.
I would suspect the same is true for Chicago, Cleveland and Detroit, though to a lesser extent.
Real summer: next-to-zero chance of even a strong cool front producing a high under 70 F in July or August. ("...The sky is falling!!!..." )
NYC is probably at the coolest end of places with a consistent "real" summer.
If you don't agree about "real" summers,
I fail to see why "real" winters should be part of a temperate climate.
In my opinion, Toronto lacks a consistent "real" summer most years.
I would suspect the same is true for Chicago, Cleveland and Detroit, though to a lesser extent.
Real summer: next-to-zero chance of even a strong cool front producing a high under 70 F in July or August. ("...The sky is falling!!!..." )
NYC is probably at the coolest end of places with a consistent "real" summer.
If you don't agree about "real" summers,
I fail to see why "real" winters should be part of a temperate climate.
I disagree. While Toronto may be more prone to cold fronts during the summer, generally your city, along with Chicago, Cleveland, and Detroit have a "real summer". Average highs in the 80s are certainly very summer-like. NYC definetly has a true summer. Highs consistently in the 80s and 90s, lows rarely dropping below 70 F. I'm glad we're far enough to the north for those cold fronts to have an effect...dries out the air and drops the temperatures for a day or two.
One could argue that places like NYC have more of a "true summer" than a "true winter".
. IMHO I think that a temperate continental climate has roughly equal length of the 4 seasons without one season dominating over the other. Not too much snow in winter (not continuous over the whole winter), not too hot in summer (no lengthy heat waves of more than a week) and spring and autumn are well defined.
Just to round out the perspectives… many areas that are located in the Temperate Continental climates would not follow that seasonal rhythm where no season dominates.
The concept of the “four seasons” was brought to the new world by the old English country people. This concept of 4 balanced seasons might have been applicable up in northern Europe (50 to 55 north latitude)…but is not really a good fit for lower latitude locations (40 north southward). On the other hand…climatologists have used 10 C (50 F) as the monthly mean temperature threshold of human comfort and plant growth. We all know that the one month with the mean temperature of 10 C is thought to coincide with the poleward limit of forests in continental locations. The real difference between the seasons in many Temperate Continental climates (like the USA/China)…is the months that have a mean temp above 50 F (10 C)…and the months that have a mean temp below 50 F.
Since we seem to be using NYC – let’s use it for the example. In NYC …7 months of the year (April through October) have a mean temp of 50 F or higher and 5 months have a mean temp under 50 F (Nov through March). What is the difference between a 84 F hot fall day in late September (like today in the NYC area)…and a warm 80 F day in May? What would be the difference in clothing/growing plants/home climate control? On the other hand…what is the difference between a cold 35 F morning in Central Park in late November (fall) and a cold 35 F morning in early February (mid winter)?
The concept of seasons worked for higher latitude Europe…but really doesn’t make sense in places like the USA or China. Most temperate continental climates from 40 latitude southward have much more warm weather (over 50 F/10 C) than cold weather (under 32 F): NYC averages 71 days when the temp falls to 32 F or lower…and 275 days when the temp gets above 50 F. There is little equal about the season in many temperate continental climates southward of 40 latitude: From mid April to late October is warm...and from November through March is cold.
Just to round out the perspectives… many areas that are located in the Temperate Continental climates would not follow that seasonal rhythm where no season dominates.
The concept of the “four seasons” was brought to the new world by the old English country people. This concept of 4 balanced seasons might have been applicable up in northern Europe (50 to 55 north latitude)…but is not really a good fit for lower latitude locations (40 north southward). On the other hand…climatologists have used 10 C (50 F) as the monthly mean temperature threshold of human comfort and plant growth. We all know that the one month with the mean temperature of 10 C is thought to coincide with the poleward limit of forests in continental locations. The real difference between the seasons in many Temperate Continental climates (like the USA/China)…is the months that have a mean temp above 50 F (10 C)…and the months that have a mean temp below 50 F.
Since we seem to be using NYC – let’s use it for the example. In NYC …7 months of the year (April through October) have a mean temp of 50 F or higher and 5 months have a mean temp under 50 F (Nov through March). What is the difference between a 84 F hot fall day in late September (like today in the NYC area)…and a warm 80 F day in May? What would be the difference in clothing/growing plants/home climate control? On the other hand…what is the difference between a cold 35 F morning in Central Park in late November (fall) and a cold 35 F morning in early February (mid winter)?
The concept of seasons worked for higher latitude Europe…but really doesn’t make sense in places like the USA or China. Most temperate continental climates from 40 latitude southward have much more warm weather (over 50 F/10 C) than cold weather (under 32 F): NYC averages 71 days when the temp falls to 32 F or lower…and 275 days when the temp gets above 50 F. There is little equal about the season in many temperate continental climates southward of 40 latitude: From mid April to late October is warm...and from November through March is cold.
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I agree with you.. I wouldn't define NYC and points south as classic continental temperate climates. Yes, places like NYC and Philadelphia fall into the temperate category but when one thinks of a continental temperate climate, it isn't the first thing that comes to mind. It's definitely on the warmer side of temperate with even some subtropical characteristics in summer. I agree with MrMarbles that areas around the southern Great Lakes constitute a classic temperate continental 4 season climate.
I agree with you.. I wouldn't define NYC and points south as classic continental temperate climates. Yes, places like NYC and Philadelphia fall into the temperate category but when one thinks of a continental temperate climate, it isn't the first thing that comes to mind. It's definitely on the warmer side of temperate with even some subtropical characteristics in summer. I agree with MrMarbles that areas around the southern Great Lakes constitute a classic temperate continental 4 season climate.
Agreed. Good overview. NYC and Philadelphia probably have more of a subtropical summer than a continental summer. Higher temperatures, higher humidity, longer stretches of hot weather, etc. Places like Minnesota for example are usually dryer and slightly cooler.
In my opinion, Toronto lacks a consistent "real" summer most years.
I would suspect the same is true for Chicago, Cleveland and Detroit, though to a lesser extent.
Real summer: next-to-zero chance of even a strong cool front producing a high under 70 F in July or August. ("...The sky is falling!!!..." )
NYC is probably at the coolest end of places with a consistent "real" summer.
If you don't agree about "real" summers,
I fail to see why "real" winters should be part of a temperate climate.
I guess it is subjective what a real summer is like. I never lived in Toronto so I'm not sure what your summers are like but in NYC if the temps were lower by a few degrees I doubt I would think summers were any less real. I'd just use AC less. Like deneb said, NYC summers are more subtropical than temperate (especially if you go by heat indexes than just temps).
I would say on average Dfa climates have "real summers".
So slowly I'm coming to the conclusion that the original Koppen Dfa is the "classical" "normal" temperate 4-season climate. Dfb is the cool/cold temperate climate. Maybe what Koppen should have done is create a third group for warm temperate (say, coldest month between -3C to 5C).
I guess it is subjective what a real summer is like. I never lived in Toronto so I'm not sure what your summers are like but in NYC if the temps were lower by a few degrees I doubt I would think summers were any less real. I'd just use AC less. Like deneb said, NYC summers are more subtropical than temperate (especially if you go by heat indexes than just temps).
I would say on average Dfa climates have "real summers".
So slowly I'm coming to the conclusion that the original Koppen Dfa is the "classical" "normal" temperate 4-season climate. Dfb is the cool/cold temperate climate. Maybe what Koppen should have done is create a third group for warm temperate (say, coldest month between -3C to 5C).
There is the 22 C summer isotherm for determining "hot summers".
Warm temperate is probably better classified on the basis of annual mean temperature. I would suggest 14 - 17 C. But then this would be limited to maritime climates as there are very few continental climates that would meet this criteria (especially with a -3 C winter isotherm).
Warm temperate is probably better classified on the basis of annual mean temperature. I would suggest 14 - 17 C. But then this would be limited to maritime climates as there are very few continental climates that would meet this criteria (especially with a -3 C winter isotherm).
…just another climate side note….
Most true temperate oceanic climates have an annual mean temperature in the same ballpark as most temperate continental climates. The southern Hemisphere is a glaring exception due to no large land masses (hence, the milder winters/cool summers). In most other regions of the world…the hot summers of temperate continental climates offset the warmer winters of temperate oceanic climates. The result is similar annual mean temperatures in both zones
In the USA for example…the annual mean temps in cities in the Temperate Oceanic Pacific Northwest…are very close to the annual mean temps in the Temperate Continental Eastern US…in fact they a few degrees cooler. Seattle has an annual mean of 11 C (52 F)….Portland, Oregon has an annual mean of 12 C (54 F)…while NYC has an annual mean of 13 C ( 55 F) and Washington DC has an annual mean of 14.5 C (58 F) . Many other temperate oceanic climates in Europe have similar annual mean temps.
Part of Koppens genius is that in relative terms… his system works for the largest number of land areas across the globe.
I guess it is subjective what a real summer is like. I never lived in Toronto so I'm not sure what your summers are like but in NYC if the temps were lower by a few degrees I doubt I would think summers were any less real. I'd just use AC less. Like deneb said, NYC summers are more subtropical than temperate (especially if you go by heat indexes than just temps).
I would say on average Dfa climates have "real summers".
So slowly I'm coming to the conclusion that the original Koppen Dfa is the "classical" "normal" temperate 4-season climate. Dfb is the cool/cold temperate climate. Maybe what Koppen should have done is create a third group for warm temperate (say, coldest month between -3C to 5C).
Well, if you go by the Dfa/Dfb border, Toronto is right on the border. The city's mean temperature in July is 22.2°C (72°F) while the airport's mean is 20.8°C (70°F). So part of Toronto is barely Dfa, while another part is Dfb. I've lived in a place a July mean of about 70°F (upstate New York). The summers were distinctly cooler, and there were occasional days that feel much like summer at all (below 70°F highs as ColdCanadian mentioned). However, most days had highs that were around 80°F, and the summer weather patterns weren't that different from New York. I'd say it had real summer, much more so than Seattle or London but definitely different than further south. A/C was not that common.
While maritime climates may have the same averages as humid continental climates, the maritime climate with a similar average is much further north. Seattle has an average only 2°F less than New York but is at 47°N while New York is at 41°N. Toronto has an average of 46-48°F while the same place on the West Coast at that latitude would have an average of 54°F or so.
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