Zone 12 Key West is as far from Florida mainland cold fronts as Cuba is from Key West

[Aceraceae 66]

By a tenth of a degree annual mean minimum (50.1 F), Key West is now zone 12(a) for 1991-2020. 

Key West is 100 miles from the Florida coast to the north and it's 100 more miles to Bainoa, the coldest town in Cuba where the all time record low of 33 F was recorded (colder than Key West record lows due to landmass and elevation)

https://www.climatestotravel.com/climate/cuba

"In northwestern Cuba, winter is pleasantly warm, but it's less warm than in the rest of the island. As mentioned, the north-west is the area that, in winter, is more exposed to short and sudden outbreaks of cool air from the United States, which can bring some days a bit cool and windy, and some rain. Occasionally, a particularly cold air mass can arrive, as happened for example in January 1977 (when the temperature dropped to 6 °C or 43 °F in Havana), in January 1981, in February 1996 (when the absolute cold record in Cuba was recorded, 0.6 °C or 33 °F in Bainoa), and in January 2010 (when a low of 4 °C or 39 °F was recorded at Havana airport). In the previous century, it seems that in January 1857 it even snowed in Cárdenas, and frosts ruined the crops."  

 

Key West is basically an ultra tropical Caribbean island (zone 12+). Miami/Beach/FTL proper (zone 11) is hard tropical with extremely rare frost, but both fall short of hypertropical zone 13 places that have never been below 50, or those most equatorial islands (Palmyra Atoll, Nauru) or the extreme hot deserts (Danakill/Dallol where it's humid without rain) that have rarely or never been below room temperature (zone 14)

The line is drawn nearly north-south here vs the classic FL NNW because both of these locations are to the SSW:

Edited January 25 by Aceraceae

[Jimbean 918]

The Dry Tortugas, Bimini Islands, and The Cays are all probably zone 12A. 

[Ubuntwo 208]

11 hours ago, Jimbean said:

The Dry Tortugas, Bimini Islands, and The Cays are all probably zone 12A. 

The Dry Tortugas seem to be 12A from 1991-2020: https://www.weather.gov/wrh/climate?wfo=key

This station, at least, remains 1-2 degrees warmer than Key West in most fronts. Not sure why they were 11A on the 2012 map.

Edited January 25 by Ubuntwo

[kinzyjr 5,490]

The station on Dry Tortugas [USC00082418] has data from 1950-1966, 1985-1999, and 2005-2022 (Current).  The averages using this data yields average annual lows just above 51F for 30 and 50 row years (since they are not continuous).  I've attached the average annual low data in case anyone wants it.

202201251945_DryTortugas_AnnualLows.xlsx

[mnorell 469]

All of the Lower Keys (all islands west of the Seven Mile Bridge) are insulated because they suffer far less from mainland air-drainage during cold events. The wedge of water known as Florida Bay is both narrower in distance and markedly shallower than the larger expanse of the Gulf of Mexico to the north of the Lower Keys, and provides less insulation for the Middle and Upper Keys (Marathon to Key Largo).  It is rare for temperatures in the Lower Keys to go below 60F, let alone 50F. In my almost 12 years in the Keys it has stayed above 50F for but a handful of hours, from Key West to Bahia Honda. It is the rare event, such as 2010, when the sustained quality of cold lowered the ocean temperature down into the low 50s (with the resultant massive fish-kills and manatee-kills) that air-temps sank to unusual levels and the all-time recorded low of 41F was matched in January 2010. And it is these longer events that drag the averages down for climatology. Remember that the Gulf Stream runs to the south of the Keys by several miles and a sustained north wind combined with a pronounced cooling in the Gulf of Mexico pretty much cancels out the stream's benefits for the island chain. In 2010 breadfruit were damaged, Pritchardia pacifica looked like hell and even the relatively stalwart coconuts throughout the Keys looked a bit pekid during that awful period. In the Upper Keys (at a nursery on Plantation Key) breadfruit was cut to the ground at about 35F, though it resprouted. But I don't think you could characterize anywhere in the Keys as "ultratropical," as you could with the Lower Antilles, where cold fronts simply don't penetrate. The Keys, Cuba and the Bahamas are all subject to cold-waves (and as mentioned above the land-mass and elevations on Cuba make that large island a quite variable place climatically) but they still all share what you would classify as a generally tropical climate.

[Aceraceae 66]

Bainoa is predicted to get colder than the lower Keys Saturday night, albeit with a higher dew point and therefore much higher relative humidity. 47 vs 50. 

[Walt 1,469]

On 1/26/2022 at 2:18 PM, mnorell said:

All of the Lower Keys (all islands west of the Seven Mile Bridge) are insulated because they suffer far less from mainland air-drainage during cold events. The wedge of water known as Florida Bay is both narrower in distance and markedly shallower than the larger expanse of the Gulf of Mexico to the north of the Lower Keys, and provides less insulation for the Middle and Upper Keys (Marathon to Key Largo).  It is rare for temperatures in the Lower Keys to go below 60F, let alone 50F. In my almost 12 years in the Keys it has stayed above 50F for but a handful of hours, from Key West to Bahia Honda. It is the rare event, such as 2010, when the sustained quality of cold lowered the ocean temperature down into the low 50s (with the resultant massive fish-kills and manatee-kills) that air-temps sank to unusual levels and the all-time recorded low of 41F was matched in January 2010. And it is these longer events that drag the averages down for climatology. Remember that the Gulf Stream runs to the south of the Keys by several miles and a sustained north wind combined with a pronounced cooling in the Gulf of Mexico pretty much cancels out the stream's benefits for the island chain. In 2010 breadfruit were damaged, Pritchardia pacifica looked like hell and even the relatively stalwart coconuts throughout the Keys looked a bit pekid during that awful period. In the Upper Keys (at a nursery on Plantation Key) breadfruit was cut to the ground at about 35F, though it resprouted. But I don't think you could characterize anywhere in the Keys as "ultratropical," as you could with the Lower Antilles, where cold fronts simply don't penetrate. The Keys, Cuba and the Bahamas are all subject to cold-waves (and as mentioned above the land-mass and elevations on Cuba make that large island a quite variable place climatically) but they still all share what you would classify as a generally tropical climate.

I lived in Key West, Florida, from June of 1970 until July of 1971 (was in the US Navy stationed there aboard ship). One can search the records, but I remember one night in January of 1971 the low temperature dropped to 47 degrees. Not a record by any means, but it sure felt cold to me. Two shipmate buddies of mine and myself camped out in Bahia Honda State Park that cold night. We had rented a tent from navy special services. We built a campfire just outside our tent to stay warm, and just sat around the fire getting drunk. I remember looking up at the coconut palms and thinking -- this is not right! How can it be this cold!  

I also remember a day or two when the temperature didn't get out of the 60s as a cold front pushed down, especially the day we visited Dry Tortugas. Aside from that, I thoroughly enjoyed the weather there. When the base grounds maintenance crews would trim coconuts of the palms, they would give us some. Below are photos from the late 1950s and mid 1960s, before I was stationed there of some of the coconut palms I got to look at every day from the ship (hull number 16 shown in photos). Alas, the base is long, long gone (closed down in March of 1973), replaced by condos and visited by cruise ships.

Lastly, the white building in two of the pics is the administration building, where the base captain worked. This building and water front area appeared in the 1959 movie Operation Petticoat, supposedly set in the south Pacific.

https://www.imdb.com/title/tt0053143/

 

[Palmarum 2,767]

On 2/7/2022 at 7:44 PM, Walt said:

... Lastly, the white building in two of the pics is the administration building, where the base captain worked. This building and water front area appeared in the 1959 movie Operation Petticoat, supposedly set in the south Pacific. ...

Great history there, and great movie. I have to watch it every now and then.

Ryan

[cbraunig 18]

Love the thread! Great info provided. Following. 

[palmsOrl 2,035]

On 1/26/2022 at 2:18 PM, mnorell said:

All of the Lower Keys (all islands west of the Seven Mile Bridge) are insulated because they suffer far less from mainland air-drainage during cold events. The wedge of water known as Florida Bay is both narrower in distance and markedly shallower than the larger expanse of the Gulf of Mexico to the north of the Lower Keys, and provides less insulation for the Middle and Upper Keys (Marathon to Key Largo).  It is rare for temperatures in the Lower Keys to go below 60F, let alone 50F. In my almost 12 years in the Keys it has stayed above 50F for but a handful of hours, from Key West to Bahia Honda. It is the rare event, such as 2010, when the sustained quality of cold lowered the ocean temperature down into the low 50s (with the resultant massive fish-kills and manatee-kills) that air-temps sank to unusual levels and the all-time recorded low of 41F was matched in January 2010. And it is these longer events that drag the averages down for climatology. Remember that the Gulf Stream runs to the south of the Keys by several miles and a sustained north wind combined with a pronounced cooling in the Gulf of Mexico pretty much cancels out the stream's benefits for the island chain. In 2010 breadfruit were damaged, Pritchardia pacifica looked like hell and even the relatively stalwart coconuts throughout the Keys looked a bit pekid during that awful period. In the Upper Keys (at a nursery on Plantation Key) breadfruit was cut to the ground at about 35F, though it resprouted. But I don't think you could characterize anywhere in the Keys as "ultratropical," as you could with the Lower Antilles, where cold fronts simply don't penetrate. The Keys, Cuba and the Bahamas are all subject to cold-waves (and as mentioned above the land-mass and elevations on Cuba make that large island a quite variable place climatically) but they still all share what you would classify as a generally tropical climate.

I consider ultratropical to be zone 12 and higher, as that's where palms like Cyrtostachys renda and trees like breadfruit survive without damage save for a once or twice per century low in the upper 30s (Havana) or low 40s (Key West).

God Bless America

-Michael

[chinandega81 364]

It says a lot that Key West saw it's all time historic low in 2010...and not in the early 1900s like Miami did. I deduce that it is because 2010 was such a prolonged event which is what made it so unusual...regardless, Miami's temperature's have steadily risen since that time, as have average and record temps. Maybe it's just the urban heat island effect. Do the residents of the Keys feel like they are warming too? Or just staying the same? Or more prone to stronger cold fronts?

[palmsOrl 2,035]

I was thinking the same thing chinandega81..