Welcome to City-Data.com Forum!
U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Weather
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
View Poll Results: Which country has a larger subtropical zone?
United States 19 26.76%
China 52 73.24%
Voters: 71. You may not vote on this poll

Reply Start New Thread
 
Old 10-09-2013, 10:43 AM
B87
 
Location: Surrey/London
11,769 posts, read 10,544,936 times
Reputation: 3094

Advertisements

Not really, it's hardly 'cherry picking' when I post the average temperatures or number of days above x temperature per year.

Cherry picking would be like doing what wavehunter did and use 1 week in December to suggest than London's winters are worse than those in Iceland, despite the averages showing that any winter month in London is sunnier, drier, warmer and calmer than November in Reykjavik.

Most people just seem to assume I am lying because the actual data doesn't fit in with the stereotype.
Reply With Quote Quick reply to this message

 
Old 10-09-2013, 10:53 AM
 
Location: Mid Atlantic USA
12,623 posts, read 13,856,346 times
Reputation: 5883
Quote:
Originally Posted by flamingGalah! View Post
Can they grow Phoenix canariensis in downtown Norfolk?


http://members3.boardhost.com/HardyP...tml?1378173825

I doubt it, but what does that have to do with overall winter average temps and which place is warmer. We know that Norfolk has a higher standard of deviation in winter. And the average lows are lower than both Solent and Portsmouth, but the highs are higher. So even if they could grow them, they would get killed with a very cold night some year. Also, the UK only has CIDP in micrclimate environments also. You don't see them growing all over the south of the UK. I saw that some were killed in Dec 2010. Over the long term I doubt they are long term cold hardy outside of warm coastal location and UHI's.


Some pics from the other forum I'm on.
These were taken on October 6th in VA Beach right outside Norfolk.

Looks like a small CIDP. Personally I wouldn't risk it there, but maybe they have a microclimate.



Other Palms.



Nice sized Oleanders.


Last edited by tom77falcons; 10-09-2013 at 11:11 AM..
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 11:06 AM
 
Location: Portsmouth, UK
13,439 posts, read 8,976,645 times
Reputation: 3915
Quote:
Originally Posted by tom77falcons View Post
I doubt it, but what does that have to do with overall winter average temps and which place is warmer. We know that Norfolk has a higher standard of deviation in winter. And the average lows are lower than both Solent and Portsmouth, but the highs are higher. So even if they could grow them, they would get killed with a very cold night some year. Also, the UK only has CIDP in micrclimate environments also. You don't see them growing all over the south of the UK. I saw that some were killed in Dec 2010. Over the long term I doubt they are long term cold hardy outside of warm coastal location and UHI's.


Some pics from the other forum I'm on.
These were taken on October 6th in VA Beach right outside Norfolk.

Looks like a small CIDP. Personally I wouldn't risk it there, but maybe they have a microclimate.



Other Palms.



Nice sized Oleanders.
Well Phoenix canariensis are quite a good 'indicator' palm, if you can grow them then you have a mild climate. They cannot take temperatures lower than -8C generally, mature ones may come back from -10C, but be totally defoliated. If you can grow CIDP's unprotected then I'd say that place has mild winters...

Yes I know CIDP's only grow longterm in the mildest micro-climates in the UK, I wasn't saying otherwise, the only places where they survived the winter of 2010 was the very mildest locations in the UK, even just inland from Portsmouth they were killed...

I see Butia & Sabal too, both can grow here as well, though Sabal's grow extremely slowly due to our cooler summers, so the mature specimens indicate the hotter summers rather than warmer winters...

We can grow Oleanders here too & yes they even flower
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 11:11 AM
 
Location: Rimini, Emilia-Romagna, Italy (44°0 N)
2,672 posts, read 3,169,450 times
Reputation: 1070
Quote:
Originally Posted by tom77falcons View Post
5.1C? Not according to your Met Office. It is 3.33C for the avg min temp in Portsmouth in winter.

Weather and climate change - Met Office
Portsmouth’s Wikipedia data unfortunately haven't a valid official source.
They seem based on this Met Office map Met Office: Regional mapped climate averages, which says a more generic 2,8°C to 5,2°C. Not 5,1°C. The same for the other months of the year.
Look at that map, in January you have 2,8°C at the northern edge of the city (Cosham), and 2,2°C in the countryside. At the same time, 5,1°C by the sea.
Such a huge urban island effect, bigger than Rome's.

Compare January lows to:
Nice airport 5,3°C.
Rome city centre 4,0°C (1961-1990).
Genoa city centre 5,1°C (1961-1990).

Portsmouth 5,1°C and Genoa city centre 5,1°C?
I think there may be some overestimation. These data seem quite misleading and they're probably useful only for a specific, sheltered point.
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 11:29 AM
 
Location: Portsmouth, UK
13,439 posts, read 8,976,645 times
Reputation: 3915
Quote:
Originally Posted by mar89 View Post
Portsmouth’s Wikipedia data unfortunately haven't a valid official source.
They seem based on this Met Office map Met Office: Regional mapped climate averages, which says a more generic 2,8°C to 5,2°C. Not 5,1°C. The same for the other months of the year.
Look at that map, in January you have 2,8°C at the northern edge of the city (Cosham), and 2,2°C in the countryside. At the same time, 5,1°C by the sea.
Such a huge urban island effect, bigger than Rome's.

Compare January lows to:
Nice airport 5,3°C.
Rome city centre 4,0°C (1961-1990).
Genoa city centre 5,1°C (1961-1990).

Portsmouth 5,1°C and Genoa city centre 5,1°C?
I think there may be some overestimation. These data seem quite misleading and they're probably useful only for a specific, sheltered point.
Did you read this thread? The stats quoted on Wikipedia are from the Southsea weather station (a Met Office weather station that is now closed)

And the mapped averages show between the stated figures, which the data on Wikipedia also comes between!

Yes it IS a huge urban heat island effect, because Portsmouth is both on its own island AND is the most densely populated place in the UK & 12th in the whole of Europe!!

There is a big difference as soon as you come off Portsea Island, all CIDP's growing north of Portsea Island were killed during 2010, even in Cosham & further inland it gets much colder. My Mum lives 8 miles north of Portsmouth & the difference in temperatures is astounding (as I used to keep weather records when I lived at home too)...

It's like talking to a brick wall on here sometimes...
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 01:29 PM
 
Location: Rimini, Emilia-Romagna, Italy (44°0 N)
2,672 posts, read 3,169,450 times
Reputation: 1070
Quote:
Originally Posted by flamingGalah! View Post
Yes it IS a huge urban heat island effect, because Portsmouth is both on its own island AND is the most densely populated place in the UK & 12th in the whole of Europe!!
It's on a small island but it isn't surrounded by deep waters. It's similar to Venice.
And the density is nothing special, around 5.000 inhabitants for square km is a normal urban density and similar to my city and many other medium cities. Portsmouth municipality is tiny and doesn't include countryside areas, so density is high.

Genoa (as well as Nice, Cannes) is much more south, sheltered by mountains, it lies along a very deep and much warmer sea, it's a large city and has an extremely high density. And it has a very mild climate, maritime, breezy and cloudy. It's basically frost free. It's the mildest and warmest city in the world for its latitude, at 44°N.

Portsmouth is "sheltered" only by gentle downs, surrounded by shallow waters, it's smaller, and much less densely populated, at a latitude 50°N.

I have some real doubt it has the same average low temperature in January.



Reply With Quote Quick reply to this message
 
Old 10-09-2013, 01:31 PM
 
Location: In transition
10,635 posts, read 16,605,918 times
Reputation: 5242
I think it's more than record low temps that dictate the growth of CIDPs but the highs as well. Downtown Vancouver hasn't recorded a temp below -10C in more than 30 years and we are in zone 9a. In theory we should be able to grow them here but the days are too cool for too long which weakens them. One extra long cold snap finishes them off here.
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 06:22 PM
 
Location: Mid Atlantic USA
12,623 posts, read 13,856,346 times
Reputation: 5883
Quote:
Originally Posted by deneb78 View Post
I think it's more than record low temps that dictate the growth of CIDPs but the highs as well. Downtown Vancouver hasn't recorded a temp below -10C in more than 30 years and we are in zone 9a. In theory we should be able to grow them here but the days are too cool for too long which weakens them. One extra long cold snap finishes them off here.

Are you that much colder than the south coast of England? The avg high in Vancouver in January is 44F vs 47F in Portsmouth. 3F is enough to make a difference? And in summer their high temps are not impressive at all. The July and August avg high is 70.5F (Solent) vs Vancouver at 72F. I'm not sure how that can make a difference. I'm sure if they are growing in Portsmouth UK they can grow a few miles away in Solent. Then why not Vancouver.

Portsmouth averages around 1564 growing degree days (base 50) and Vancouver averages 1370. So the CIDP would grow slightly slower there, but they are pretty slow growing anyway.

Compared to the Med, I think it will be a hundred years before those CIDP in Portsmouth reach full mature height. Considering Rome gets 3644 GDD vs 1564 in the UK, lol.
Reply With Quote Quick reply to this message
 
Old 10-09-2013, 08:32 PM
 
Location: In transition
10,635 posts, read 16,605,918 times
Reputation: 5242
Quote:
Originally Posted by tom77falcons View Post
Are you that much colder than the south coast of England? The avg high in Vancouver in January is 44F vs 47F in Portsmouth. 3F is enough to make a difference? And in summer their high temps are not impressive at all. The July and August avg high is 70.5F (Solent) vs Vancouver at 72F. I'm not sure how that can make a difference. I'm sure if they are growing in Portsmouth UK they can grow a few miles away in Solent. Then why not Vancouver.

Portsmouth averages around 1564 growing degree days (base 50) and Vancouver averages 1370. So the CIDP would grow slightly slower there, but they are pretty slow growing anyway.

Compared to the Med, I think it will be a hundred years before those CIDP in Portsmouth reach full mature height. Considering Rome gets 3644 GDD vs 1564 in the UK, lol.
Well, I think we get slightly colder but for longer. The South coast of England is in a very favoured location for the latitude. Also, we get a LOT more rain than they do.. that could also have a large impact on CIDPs as I don't think they like to be waterlogged when it's cold out. It would be interesting to know the minimum amount of growing degree days that will enable a CIDP to survive.. maybe it's only around 1500 and Portsmouth squeaks in but Vancouver falls a bit short...
Reply With Quote Quick reply to this message
 
Old 10-10-2013, 12:14 AM
 
Location: Mid Atlantic USA
12,623 posts, read 13,856,346 times
Reputation: 5883
Quote:
Originally Posted by deneb78 View Post
Well, I think we get slightly colder but for longer. The South coast of England is in a very favoured location for the latitude. Also, we get a LOT more rain than they do.. that could also have a large impact on CIDPs as I don't think they like to be waterlogged when it's cold out. It would be interesting to know the minimum amount of growing degree days that will enable a CIDP to survive.. maybe it's only around 1500 and Portsmouth squeaks in but Vancouver falls a bit short...

Most plants, palms included, don't grow much at all below 50F. The base temp for corn and tomatoes is 50F, for cotton it is 60F, peanuts=56F, potatoes and sunflowers=45F and the lowest wheat, barley, rye, oats, asparagus, lettuce=40F. CIDP grow very slowly as it is, which is why I think they will grow so much more slowly in the UK with the minimal amount of GDD they get with a base of 50F.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

Quick Reply
Message:


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Weather

All times are GMT -6.

© 2005-2024, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Contact Us - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37 - Top