Most Northern Subtropical climate in the world? (places, seasons, frost)

[dxiweodwo]

Originally Posted by JohnB2345

Ahh, but there are other definitions of subtropical. The Glenn Trewartha definition is of anywhere where 8 or more months of the year have a mean of over 10C. Also per the John F Griffith definition, it is anywhere where the coldest month has a mean of at least 6C, irrespective of what the warmest month is - and on that definition, the most northerly place with a subtropical climate is the town of Poolewe - coldest month average there is 6C, and that happens only because of how the Gulf Stream happens to hit that part very firmly.

According to the John F Griffith definition...that would mean places like Nashville, TN or Knoxville or virtually the whole state of TN isn't subtropical...and cities like Atlanta or Birmingham are "barely" or borderline subtropical. Which makes a lot more sense than the 0C (32F) definition which would put about 60% of KY and the east coast all the way up to NYC in the Subtropical zone and don't even get me started on the -3C (26.6F) definition if you have a mean temp of 26F in January you are not subtropical by any means!!!

To me "subtropical" means to have some tropical and some temperate characteristics...there's barely any tropical characteristics when you get say north of 33N in the U.S (somewhere like Macon, GA comes to mind)

[ChesterNZ]

Originally Posted by Derek40

Probably the shores of the Black Sea - ie in Russia - would qualify as the furtherest north.
Haven't read this whole thread to see if it is mentioned before.
Places like Japan and Korea are close but are more continental in climate, have hot summers and cold winters.
Going south, Perth would classify in my book, average yearly temp 12.5-24.5C seesm more than adequate.
This to me is more of an indication than purely yearly mean temp.
Below Bunbury-Busselton on the west coast would not.
Sydney would not qualify, not even Newcastle. The former has too many months of coolish weather, ie cool > warm weather. Average temp in Sydney is 13- 21.6C
Subtropical probably starts at around Forster-Taree in NSW on the east coast.

Sydney ought to qualify. There are heaps of palm trees in Sydney (although probably no coconut palms). Sydney observatory apparently has a record low of 2.5 C. Even Brisbane and the Gold Coast has recorded much lower than that. Ditto for various locations in Florida.

[ChesterNZ]

Originally Posted by dxiweodwo

According to the John F Griffith definition...that would mean places like Nashville, TN or Knoxville or virtually the whole state of TN isn't subtropical...and cities like Atlanta or Birmingham are "barely" or borderline subtropical. Which makes a lot more sense than the 0C (32F) definition which would put about 60% of KY and the east coast all the way up to NYC in the Subtropical zone and don't even get me started on the -3C (26.6F) definition if you have a mean temp of 26F in January you are not subtropical by any means!!!

To me "subtropical" means to have some tropical and some temperate characteristics...there's barely any tropical characteristics when you get say north of 33N in the U.S (somewhere like Macon, GA comes to mind)

Yes, there are certainly very few (if any) subtropical plants that could survive a winter in NYC. Even Atlanta is marginal.

[Derek40]

Originally Posted by ChesterNZ

Sydney ought to qualify. There are heaps of palm trees in Sydney (although probably no coconut palms). Sydney observatory apparently has a record low of 2.5 C. Even Brisbane and the Gold Coast has recorded much lower than that. Ditto for various locations in Florida.

Using things like record low temperatures are a trap for young players.
I have lived in Sydney for over 20 years of my life, it is not subtropical.
Whereas the far north of NSW, where I lived for 6 years, definitely is subtropical - and that is just south of Brisbane.
Places like Brisbane may get the odd cool snap here and there, but for the vast majority of winter - the winter is a non-event.
Sydney's winter is much, much longer than Brisbane's - some 5 months vs about 6-8 weeks up north- like where I lived south of Brizzy.
Cold weather can hang around in Sydney right up until late November - this would NEVER happen in Brisbane.
The same applies to Florida - any temps below freezing are very short-lived.
Winter never really "sets in" in these places, which is what sets them apart from temperate climates like Sydney.
Palm trees may grow in Sydney, but they do not flourish in Sydney.

[wavehunter007]

Originally Posted by Derek40

Using things like record low temperatures are a trap for young players.
I have lived in Sydney for over 20 years of my life, it is not subtropical.
Whereas the far north of NSW, where I lived for 6 years, definitely is subtropical - and that is just south of Brisbane.
Places like Brisbane may get the odd cool snap here and there, but for the vast majority of winter - the winter is a non-event.
Sydney's winter is much, much longer than Brisbane's - some 5 months vs about 6-8 weeks up north- like where I lived south of Brizzy.
Cold weather can hang around in Sydney right up until late November - this would NEVER happen in Brisbane.
The same applies to Florida - any temps below freezing are very short-lived.
Winter never really "sets in" in these places, which is what sets them apart from temperate climates like Sydney.
Palm trees may grow in Sydney, but they do not flourish in Sydney.

Zone classification in climates has always been a hot topic of debate…and the subtropical zone (25 - 40 latitude roughly) is always the biggest debate. So I have always tried to come at this problem by looking at it from another angle: Let’s use the Polar Climates (F) and the Boreal Climates, or “Subpolar” climates (E):

The Boreal Climates (or “Subpolar”) climate should be to Polar climates… what Subtropical climates are to Tropical climates. This means to me, that for a portion of the year - sensible weather in the Boreal climate closely resembles the sensible weather in the true Polar climate. So if you look at monthly temp data for a portion of the year in a Boreal climate like Siberia or Western Canada…they should have weather conditions very similar to Polar climates for a portion of the year. Yakursk, Siberia (62 North) in the “subpolar” climate has a January mean temp of -43 C (-46 F)…and Sagastyr, Siberia (73 N) in the “polar” climate has a January mean temp of -37 C (-34 F) in January. So many stations in the Boreal Zone…have sensible weather conditions close to true Polar climates in the low sun period (and this is when they are often climatically connected and really are one climate zone). However it is also true, that in the high sun period (summer) – Boreal climates are significantly warmer than Polar climates (Churchill or Fort Vermillion, Canada are warmer in summer than Coppermine or Upernivik, Greenland for example).

So it seems that the “sub” of a climate…means that for a portion of the year, mean temps (and even sensible weather often) is very close to mean temps in the true “zone” in question (tropical, polar, desert…etc). If we look at the subtropical zones… yes, maybe there are sitituations like Sydney in Australia that seem to not have a period of “tropical conditions” resembling their non-sub counterparts …but these types of climates are the exception not the rule. In many more examples climates and their “sub” zones often share many of the same traits: In the high sun period… mean temps and sensible weather conditions are often not much different in Brisbane (C) from Darwin (A)…or in New Orleans or Savannah (C) from Miami or Havana (A).

This is what I think (?) climatologists like Koppen were trying to accomplish when they created “sub” zones: Climates where are good portion of the year are closely tied to their "true" non-sub zones.

.

[ChesterNZ]

Certainly the American Southeast has summers comparable to those of the Carribean and central America, but far more pronounced winter cold. The same comparison could probably be made for the dry subtropics of the Southwest (with the exception of the coast).

However, I think the likes of LA and Sydney should be classified as subtropical even though they have non-tropical summers. Their warmth on an annual basis is such that they ought to be differentiated from places like Christchurch.

I would modify the Koppen system to make a coldest month mean temp of 12 C the cutoff for the Cfa/Cwa climates rather than the ridiculous 0 C (or, even worse, -3 C!). Of course there's nothing magical about 12 C -- I chose it because it only just included Sydney. A coldest month mean in the 10 - 15 C range seems appropriate. The key thing is that the winters are generally mild with infrequent frosts (and when they do experience frost it is fairly light and short-lived).

[MrMarbles]

Originally Posted by ChesterNZ

Certainly the American Southeast has summers comparable to those of the Carribean and central America, but far more pronounced winter cold. The same comparison could probably be made for the dry subtropics of the Southwest (with the exception of the coast).

However, I think the likes of LA and Sydney should be classified as subtropical even though they have non-tropical summers. Their warmth on an annual basis is such that they ought to be differentiated from places like Christchurch.

I would modify the Koppen system to make a coldest month mean temp of 12 C the cutoff for the Cfa/Cwa climates rather than the ridiculous 0 C (or, even worse, -3 C!). Of course there's nothing magical about 12 C -- I chose it because it only just included Sydney. A coldest month mean in the 10 - 15 C range seems appropriate. The key thing is that the winters are generally mild with infrequent frosts (and when they do experience frost it is fairly light and short-lived).

What would, then, be the cutoff between subtropical and true tropical climates? Right now it is 18C. Difference between 12C and 18C is almost too small to justify making an entire climate category IMO. In the US, it would be only a few hundred miles deep, say from central Florida to southern Georgia after which there would be a very wide continental zone from Central Georgia to Quebec city.

[ChesterNZ]

Originally Posted by MrMarbles

What would, then, be the cutoff between subtropical and true tropical climates? Right now it is 18C. Difference between 12C and 18C is almost too small to justify making an entire climate category IMO. In the US, it would be only a few hundred miles deep, say from central Florida to southern Georgia after which there would be a very wide continental zone from Central Georgia to Quebec city.

You could make the limits 10 C and 20 C, respectively, as these are nice, round numbers and would allow for a much wider range. This would characterise Auckland as marginally subtropical which is a little generous, but then there are quite a few subtropical plants growing in Auckland, so it makes sense intuitively.

[wavehunter007]

Originally Posted by ChesterNZ

Certainly the American Southeast has summers comparable to those of the Carribean and central America, but far more pronounced winter cold. The same comparison could probably be made for the dry subtropics of the Southwest (with the exception of the coast).

However, I think the likes of LA and Sydney should be classified as subtropical even though they have non-tropical summers. Their warmth on an annual basis is such that they ought to be differentiated from places like Christchurch.

I would modify the Koppen system to make a coldest month mean temp of 12 C the cutoff for the Cfa/Cwa climates rather than the ridiculous 0 C (or, even worse, -3 C!). Of course there's nothing magical about 12 C -- I chose it because it only just included Sydney. A coldest month mean in the 10 - 15 C range seems appropriate. The key thing is that the winters are generally mild with infrequent frosts (and when they do experience frost it is fairly light and short-lived).

I think you might be a little confused about climate classifications…only because it is so darn confusing that Trewartha modified the original Koppen climate classification, without changing the letters enough:

In the original 1899 Koppen system…climates that fell into his C Climates (Mesothermal) zone when their coldest month was below 18 C (64.4 F) but above -3 C (26.6 F). Koppen’s empirical data showed that the coldest month in this zone (which he broadly defined as temperate rainy climates)… was the rough line that coincided with the equatorward limit of frozen ground and snow cover that lasted less than 30 days. However, Koppen never thought of this (or called it) subtropical. This was just a huge zone - that put places like Dunedin (temperate oceanic) or Berlin (temperate continental) in the same zone as Brisbane or deep south China (In the USA places like Seattle, Chicago or Denver …were in the same zone as Orlando, FL or New Orleans, LA). Europe, eastern Australia, much of the central/eastern USA, and much of China was in this orginal zone. Here is the original map:

KOPPEN:



It was Trewarth…later in the 1950, and 1960’s who (along with a growing number of scientists) thought Koppens C Mesothermal zone was too broad. Trewartha intoroduced the “Subtroical Zone (both Cf and Cs). Locations that fell into this Subtropical zone (C) only had the requirement that 8 or more months had a mean tempreture of 10 C (50 F) or higher. There was no cold month cut off or minimum. However, nearly 99% of all the climates that fell into this new “subtropical zone” had a coldest monthly mean well above 0 C (or – 3 C). If you consider any climate in Trewarths subtropical zone (meaning a climate that has 8 or more months with a mean temp of 10 C (50 F)… even in the northern portions subtropical east Asia where the world’s strongest winter monsoon is present - places like Tokyo (37 N) or Shanghai (33 N) have coldest month mean temperatures of 3 or 4 C (38/39 F). In the USA eastern subtropical zone they are even higher: Even at the northernmost/interior locations the coldest monthly mean temps at stations like Raleigh, NC (35 N), Atlanta, GA (34 N) or Dallas Tx (34 N) are in the 5 to 7 C (40 to 45 F). No station that I know off in Trewarths C or Subtropical zone anywhere in the world… has a cold month mean temp of less than 3 C (38 F)…and those are only in East Asia where the worlds strongest winter monsoon is located.

Here is a map of Trewarthas climate classification (you can see his C or subtropical zone, is located in the southern half of Koppen’s orginal C or Mesothermal zone):

TREWARTH (AND HIS NEW C/Subtropical zone)




Koppen was a genius (especially considering what he had to work with)…and his zone of mesothermal climates are all really in the same zone…but I prefer Trewarths system for the sole reason that it shows the difference from temperate climates and subtropical climates.


.

[wavehunter007]

Originally Posted by MrMarbles

What would, then, be the cutoff between subtropical and true tropical climates? Right now it is 18C. Difference between 12C and 18C is almost too small to justify making an entire climate category IMO. In the US, it would be only a few hundred miles deep, say from central Florida to southern Georgia after which there would be a very wide continental zone from Central Georgia to Quebec city.

According to Koppen…the 18 C line is a much more important climate line: 18 C (65 F) for all months is the realm of the megatherms – plants that need continuously high temperatures (say coconut palms). Things that grow in south Florida like mangos, key lime, ...etc would not make it in a zone that falls below 65 F. However, I think Trewarths designation is the best. Georgia and southern Quebec should not be in the same climate zone!

How often do you run into this in the swamps of Quebec? Lol.