Miami And The Tropic Of Cancer

[sarasota alex]

Tropical Cyclones can and do form outside of the Tropical zone. Subtropical and Extratropical Cyclones can and do form within the Tropical zone. No one seems to be uncomfortable with those concepts. Just because the same adjective "tropical" is used to mean more than one concept, doesn't mean that those concepts have to somehow define each other. Kinda unscientific too.

It's like a chemical term "denaturation". A denaturation of a protein means altering the structure of that protein a certain way. A denaturation of alcohol means adding poison to make it unsuitable for human consumption. A denaturation of Uranium means decreasing the concentration of fissile isotopes in the mixture. Totally unrelated but use the same word to describe them.

If you look at the Wikipedia article on the tropical climate http://en.wikipedia.org/wiki/Tropical_climate, you would find a single photograph of an example of a place with a tropical climate. That place is Naples, Florida.

[amazondk]

Alex, you are correct according to the map of the Koppen climate zone map that Naples is considered tropical. But, it still is not in the tropics. It is then an extra-tropical tropical like climate I guess if one applies latitude to what makes the tropics or not. When I lived in são Paulo I used to frequent the city in the Mantiqueira mountains some 150 kms away called Campos do Jordão. This city is a has mostly Swiss Alpine style houses and from time to time in the winter gets below freezing at night. On these nights the streets are packed in the oustide bars by people drinking hot wine drinks, eating foundue and locally raised rainbow trout in outdoor cafes heated with exterior gas heaters. The big thing to buy there are wool sweaters. It is a very beautifuil area and a unique little city. I always figured it was in the tropics though. As one drives from São Paulo on the expressway to Rio de Janeiro just before the turn off to Campos you go acoss the Troipc of Capricorn and there is a big sign saying so. The place where the sign is has an elevation of about 600 meters above sea level and Campos do Jordão is at about 1600 meters above sea level. I don´t think a climate classification makes much difference anyway. What does is to enjoy the places.

Swizterland in the troipcs

[Pez]

A tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures above 18 °C (64 °F). Unlike the extra-tropics, where there are strong variations in day length and temperature, with season, tropical temperature remains relatively constant throughout the year and seasonal variations are dominated by precipitation.

I just copied this from the same Wikipedia page which shows the picture of Napes FL as an example of a tropical climate. That picture was obviously taken pre 2009 / 2010 winter. I don't think the coconuts are looking as "tropical" these days. While I don't agree with the Naples picture (example of how anybody can edit Wikipedia), I do agree with Köppen's description of the tropics not having much variance in seasons. The days should not get significantly shorter nor should there be any drastic swings in temperature. Everywhere in Florida, including the keys, has much shorter days and considerable dips in temperature during the winter months. I fished out of Key West last December and it was DAMN cold (mid to upper 40's one of the mornings if i remember correctly). When I think tropical, i think of somewhere I can go in the middle of winter and be guaranteed of wearing flip flops, shorts, and a t shirt.

As far as growing palms, it doesn't even matter what your area or climate is classified as. Either you can grow certain palms or you can't. Unless you are well inside the tropics or on an island in the middle of the ocean, you're going to have issues from time to time.

[sarasota alex]

Alex, you are correct according to the map of the Koppen climate zone map that Naples is considered tropical. But, it still is not in the tropics. It is then an extra-tropical tropical like climate I guess if one applies latitude to what makes the tropics or not. When I lived in são Paulo I used to frequent the city in the Mantiqueira mountains some 150 kms away called Campos do Jordão. This city is a has mostly Swiss Alpine style houses and from time to time in the winter gets below freezing at night. On these nights the streets are packed in the oustide bars by people drinking hot wine drinks, eating foundue and locally raised rainbow trout in outdoor cafes heated with exterior gas heaters. The big thing to buy there are wool sweaters. It is a very beautifuil area and a unique little city. I always figured it was in the tropics though. As one drives from São Paulo on the expressway to Rio de Janeiro just before the turn off to Campos you go acoss the Troipc of Capricorn and there is a big sign saying so. The place where the sign is has an elevation of about 600 meters above sea level and Campos do Jordão is at about 1600 meters above sea level. I don´t think a climate classification makes much difference anyway. What does is to enjoy the places.

Swizterland in the troipcs

Don, I'd love to visit there one day

[amazondk]

Alex,

I am sure you would love the place. The drive up there is incredible as the road winds up the steep mountains and over the pass to Campos.

dk

[Jason in Orlando]

We need a "Pulling my hair out!" smiley.

Jason

[Trópico]

I realize the Tropic of Cancer is an important area on the earth.

What makes the sun appear directly overhead on the summer solstice? I know the tilt of the earth has something to do with it but :

*Is the curve of the earth steeper or different in that part of the world and that also contributes? It appears so when you look at Miami and the tropics ( from the side ) of a Google Earth download

* Is it necessary to go somewhat below the Tropic of Cancer to get tropical level sunlight intensity, vegetation etc. or is Miami close enough to the tropic line to get those benefits most of the year?

*If you had to compare latitude 25 N to the true official tropics ( 23N - 23 S) how does it compare?

I am curious about this as I would like to go to San Juan, Puerto Rico and compare it with Miami. But if they are very a like then I could save money and just stay here.

Most of your questions are answered by one unmentioned fact: The ocean/landmass influence. If Miami were to lie in the middle of the ocean for sure it would be true tropical (as in record low > 50°F). This is the main difference between Miami, and San Juan, PR. In San Juan you can only get chilly air out of an A/C unit vent or refrigerator. Also, most of the year is quite pleasant as the sea breeze regulates temperatures both up and down (typical daytime high/nighttime low difference is 10°F). Hence you can see very large mango trees, breadfruit, Lipstick palm clumps just like in Hawaii, and unlike Miami. So there lies the main difference, not counting the fact that San Juan is quite closer to the equator.

Now, turn the globe around and look at the arrangement of land masses at the southern hemisphere and see how the ocean currents, etc modify the climate in every location that lies at an equivalent Miami location, but in the south.

So the answer to your staying here or not question relates on what kind of plants you would like to grow well long term.

[amazondk]

I guess that would be pretty much true Frank. Although besides being surrounded by water Puerto Rico is in the tropics. The geography of South America is much different from North Amercia, therefore the impact of cold fronts is much different. Different from the southeast cost of Florida there is a cold ocean current running up along the coast in latitudes similar to Miami. I have posted some climate charts some of wich I have posted before. If you compare Miami to Parangua in soutern Brazil the average data is pretty much the same for the same latitudes north and south. But, Paranagua never gets freezes even though it does get affected by cold fronts from Antarctica. The average temperatures are much the same, but since it never freezes you could consider it to be more tropical than Miami. Although it is still sub tropics. Coconuts do grow down most of the Brazilian coastline outside of the tropics. San Juan on the other hand does not get the impact of cold fronts like inland cities in Brazil of similar latitudes. And, I posted Manaus again, which is about as stable as a climate can get.

Miami

Paranagua, Parana, Brazil

San Juan, PR

Manaus

[Walt]

I realize the Tropic of Cancer is an important area on the earth.

What makes the sun appear directly overhead on the summer solstice? I know the tilt of the earth has something to do with it but :

Yes, it's due to the tilt of the earth.

The earth's axis is titled 23.5 degrees (from an imaginary vertical line), and because of this inclination, the sun is directly overhead (at noon) on the Tropic of Cancer (23.5 degrees from the north of the equator) on June 21st (summer solstice), and on December 21st (winter solstice) at the Tropic of Capricorn (23.5 degrees south of the equator).

But at the equator the sun is directly overhead twice each year, once on March 21st (vernal equinox) and again on September 23rd (autumnal equinox). If there wasn't any tilt, there would be no seasons and day length would be exactly 12 hours of light and 12 hours of darkness.

I am curious about this as I would like to go to San Juan, Puerto Rico and compare it with Miami. But if they are very a like then I could save money and just stay here.

I've been to both Miami and Puerto Rico many times. All I know is, the sun's rays (solar radiation/energy) are more direct (higher overhead) in Puerto Rico during the winter months than in Miami, plus the day length is longer than in Miami; hence, it is warmer in Puerto Rico during the winter months -- and also more tropical.

[amazondk]

Walt,

The difference between Miami and San Juan is 7 degrees, which is not al lot. Unfortunately the graph I posted does not have daylight hours for San Juan. But, they must be not too differrent from Miami. I would say that the ocean influence is greater than the day length between San Juan and Miami.

dk

[displaced_floridian]

I agree, it's the continental air masses that affect Miami in Winter that makes it's climate so different from San Juan's.

If Miami were straight north from SJ PR at 25.6N latitude, the climate would be truly tropical & not much different from coastal Puerto Rico. Bermuda at 32.18N, has never been below 45*F, though the Winters are cool & rainy.

[Walt]

I wasn't making a case about Miami's climate vis a vis Puerto Rico's per se. I was responding to the poster's questions concerning the "tilt" of the earth, that the earth's 23.5 degree tilt is the reason the sun is at it's zenith on June 21st at the Tropic of Cancer at noontime, and there's more "tropical level sunlight intensity" at 23.5 degrees than in Miami.

Hence, my answer was that Puerto Rico, lying closer to the equator (approximately 7 degrees closer, at 18.46 degrees N), gets more "direct" sunlight and more "duration" of sunshine during the winter months than Miami does; hence, PR is warmer based on those two factors alone -- notwithstanding further factors, such as PR being totally surrounded by relatively warm ocean water.

Yes, the ocean water is a big factor, and most likely the biggest factor, at least in Miami at 25.78 latitude North latitude. That's why Freeport, Grand Bahama's (more northerly than Miami at 26.52 degrees N, but totally surrounded by relatively warm ocean water) January's low temperatures average five degrees higher than Miami's.

While the thermal effect of water holds nighttime temperatures up, it has a converse effect during the day once air temperature tries to rise above the water temperature (water holds the air temperature down, as heat then flows from hot (air) to cold (water).

And San Juan, Puerto Rico's January temperatures are signifigantly higher than either Miami's or Freeport's.

Miami (January average): high: 75 low: 59 all-time low: 30

Freeport (January average): high: 74 low: 64 all-time low: 41

San Juan (January average): high: 83 low: 70 all-time low: 61

[Don_Licuala]

Places that are truly tropical stay above 60ºF or 15ºC year round.

If it goes below that, the locals are in a panic..

Subtropical climates will see temps stay above freezing year-round.

Warm-temperate climates stay above about -5ºC.

Of course, these areas have long, warm wet summers.

Mediterranean and west-coast climates are different with less temperature variation, and rain usually in the cool months.

Miami will see the effects of a continental cold front a couple of times per winter, and waking up in the 40's down this way is frigid. The air is humid so you feel pretty darn cold outside. Head into the Caribbean, and the circulating water current and lower latitude work to keep temps in the 60º-90º range year round. From the Bahamas to Aruba you can swim year round in the ocean.

DL

[Walt]

I lived (curtesy of the US Navy) in Key West, Florida, for 13 months (June ? 1970 to July 19, 1971). I can state empirically Key West's winter time's temperatures, while nice overall, didn't compare to San Juan, Puerto Rico's.

I remember on several ocassions during the winter when cold fronts would push down and there would be advective cooling. I recall on some of these days it was overcast, and with the wind it felt uncomfortably cool to where one needed to wear a jacket. The conches (the locals) would bundle up, as they were spoiled and weren't used to the infrequent cold spells.

I also recall one night in January of 1971 it got down to 47 degrees F (8.25C) with a strong breeze. I distinctly recall that night as me and some shipmate buddies of mine were camping on Bahia Honda Key State Park, and we had a camp fire going to help stay warm. I remember looking up at the swaying coconut palms on the beach and thinking how the cold seemed so out of place.

But the above being said, I enjoyed Key West's climate overall.

[sarasota alex]

Places that are truly tropical stay above 60ºF or 15ºC year round.

If it goes below that, the locals are in a panic..

Subtropical climates will see temps stay above freezing year-round.

Warm-temperate climates stay above about -5ºC.

Of course, these areas have long, warm wet summers.

Mediterranean and west-coast climates are different with less temperature variation, and rain usually in the cool months.

Miami will see the effects of a continental cold front a couple of times per winter, and waking up in the 40's down this way is frigid. The air is humid so you feel pretty darn cold outside. Head into the Caribbean, and the circulating water current and lower latitude work to keep temps in the 60º-90º range year round. From the Bahamas to Aruba you can swim year round in the ocean.

DL

OK so Sarasota is warm temperate, even though we have coconuts. And Havana, Cancun and San Jose, Costa Rica are all subtropical, since temperatures frequently falls below 60F during winters there. Havana hit 39F in January of 2010, and Cancun had temps in the high 40s a few time during the last couple of winters.

This clearly doesn't match any of the accepted definitions of Tropical, Subtropical or Warm Temperate. Also you can swim on Miami Beach all year around and many of the winters you could also do so in Sarasota.

[jasons]

It's real simple. We're talking about two separate things here:

You can live "in the tropics" (between the latitude lines)...

You can live "in a tropical climate" (whatver Koeppen defines that as)...

Or, you can be really lucky and have both....but technically they are mutually exlusive.

Edited January 3, 2012 by jasons