000
NOUS42 KKEY 052104
PNSKEY

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE KEY WEST FL
404 PM EST TUE JAN 5 2021

...2020 WAS A YEAR OF TOP TENS FOR FLORIDA KEYS CLIMATE RECORDS...

LAST YEAR WAS ANOTHER WARM ONE FOR THE FLORIDA KEYS, WITH AN AVERAGE 
ANNUAL TEMPERATURE OF 80.1 DEGREES FAHRENHEIT AT BOTH FLORIDA KEYS 
CLIMATE SITES. THIS WAS 2.3 AND 1.6 DEGREES ABOVE THE CLIMATOLOGICAL 
NORMAL VALUE (ROLLING 30-YEAR AVERAGES, CURRENTLY SPANNING 1981-
2010) AT KEY WEST AND MARATHON, RESPECTIVELY. THESE AVERAGES ALSO 
RANKED IN THE TOP FIVE FOR WARMEST YEARS ON RECORD AT BOTH 
LOCATIONS. IT WAS THE 2ND WARMEST YEAR AT KEY WEST AND 4TH WARMEST 
AT MARATHON. THE WARMEST YEAR ON RECORD FOR BOTH SITES WAS 2019, 
WITH AVERAGE ANNUAL TEMPERATURES OF 80.3 DEGREES AT KEY WEST AND 
81.7 AT MARATHON.

HELPING TO FUEL THE WARMER YEAR WAS AN ABUNDANCE OF WARMER LOW 
TEMPERATURES, INCLUDING A PLETHORA OF WARM MINIMUM TEMPERATURE 
RECORDS. BETWEEN THE TWO LOCATIONS THERE WERE 103 DAILY WARM MINIMUM 
TEMPERATURE RECORDS SET OR TIED IN 2020 -- KEY WEST RECORDING MORE 
THAN TWO-THIRDS OF THEM. OVER THE COURSE OF THE YEAR THERE WERE ALSO 
FIVE MONTHS WITH A MONTHLY WARM MINIMUM TEMPERATURE RECORD SET OR 
TIED AT KEY WEST: MARCH (79 DEGREES, TIE), APRIL (81, TIE), MAY (83, 
TIE), JUNE (86, TIE), AND SEPTEMBER (86, NEW MONTHLY RECORD THAT 
OCCURRED ON THREE DAYS). 

IN FACT, KEY WEST HAD THE MOST DAYS ON RECORD LAST YEAR FOR LOW 
TEMPERATURES OF 80 DEGREES OR HIGHER. AT 122 DAYS (A THIRD OF THE 
YEAR) IT WAS MORE THAN DOUBLE THE LONG-TERM AVERAGE OF 53 DAYS. THE 
NEXT CLOSEST YEAR FOR LOWS OF 80 OR HIGHER IS 2015, WHEN 120 SUCH 
DAYS WERE RECORDED. COPIOUS WARM LOW TEMPERATURE READINGS INFLUENCED 
THE AVERAGE ANNUAL TEMPERATURE TO HELP BOOST IT TO THE 2ND WARMEST 
SPOT. AN AVERAGE LOW TEMPERATURE FOR THE YEAR OF 75.8 DEGREES RANKED 
SECOND ONLY TO 2019'S AVERAGE OF 75.9 DEGREES. THE AVERAGE HIGH 
TEMPERATURE OF 84.3 DEGREES RANKED 6TH, THE WARMEST BEING 85.5 
DEGREES IN 1957. NINE OF THE TOP TEN YEARS FOR MOST NUMBER OF DAYS 
WITH LOWS OF 80 DEGREES OR HIGHER HAVE OCCURRED SINCE 2000 AND SEVEN 
OF THOSE OF HAVE BEEN SINCE 2010.

LOOKING AT A HIGHER THRESHOLD, LOWS EQUAL TO OR GREATER THAN 85 
DEGREES, 2020 ALSO TAKES THE TOP SPOT WITH 24 SUCH DAYS. THIS WAS A 
50% INCREASE OVER THE PREVIOUS TOP SPOT OF 16 DAYS IN 2007. OF THE 
TOP TEN YEARS (THIRTEEN YEARS WHEN FACTORING IN A 9TH PLACE 5-WAY 
TIE) FOR NUMBER OF DAYS WITH LOWS 85 AND HIGHER, EIGHT HAVE OCCURRED 
SINCE 2000 AND SEVEN OF THOSE HAVE BEEN SINCE 2010.

A STATEMENT THAT IS PROBABLY OBVIOUS TO MANY, IS THAT IT WAS ALSO A 
WET YEAR. MARATHON MEASURED 64.55 INCHES OF RAINFALL LAST YEAR, 
PUTTING IT AT 18.38 INCHES ABOVE NORMAL AND THE 2ND WETTEST YEAR ON 
RECORD. KEY WEST MEASURED 52.30 INCHES OF RAINFALL, 12.47 INCHES 
ABOVE NORMAL. WHILE 52 INCHES OF RAIN AT KEY WEST WAS NOT QUITE 
ENOUGH TO BREAK INTO THE TOP TEN, IT DID MANAGE TO RANK IN THE TOP 
TEN PERCENT OF WETTEST YEARS IN ITS 150-YEAR HISTORY.

KEY WEST'S WETTEST DAY OF THE YEAR, SEPTEMBER 12TH, RECORDED 9.37 
INCHES OF RAINFALL, BOOSTING SEPTEMBER TO THE WETTEST MONTH OF THE 
YEAR. THIS WET SEPTEMBER DAY WAS THE RESULT OF TROPICAL STORM SALLY 
PASSING NORTH OF THE KEYS AND WAS FURTHER AMPLIFIED BY ANOTHER ROUND 
OF EXTREMELY INTENSE RAINFALL DURING THE EVENING HOURS. THE LATTER 
BEING FROM CUBAN THUNDERSTORM OUTFLOW RACING ACROSS THE STRAITS AND 
SPARKING OFF A THUNDERSTORM THAT PRODUCED FOUR INCHES OF RAINFALL IN 
JUST ONE HOUR IN KEY WEST.

WHILE MARATHON'S WETTEST DAY OF THE YEAR WAS ALSO SEPTEMBER 12TH, 
WHEN 8.13 INCHES OF RAINFALL WAS RECORDED, IT ONLY HELPED GET 
SEPTEMBER TO THE 4TH WETTEST MONTH OF THE YEAR WITH 10.20 INCHES OF 
RAINFALL. THREE ADDITIONAL MONTHS, MAY, JULY, AND OCTOBER, SURPASSED 
THE TEN INCH MARK, WITH 15.66, 10.59, AND 13.39 INCHES OF RAINFALL 
RESPECTIVELY.

NOT ONLY DID THE SEPTEMBER 12TH RAINFALL TOTALS SET NEW DAILY 
RECORDS FOR THE MONTH OF SEPTEMBER AT BOTH CLIMATE LOCATIONS, THEY 
ALSO HAVE THE DISTINCTION OF BEING SOME OF THE WETTEST DAYS ON 
RECORD. IT MARKED THE 5TH WETTEST DAY EVER FOR THE KEY WEST AREA AND 
THE 3RD WETTEST FOR THE MARATHON AREA. MARATHON ALSO EXPERIENCED 
ANOTHER WET DAY ON MAY 14TH WITH 5.76 INCHES OF RAINFALL, THE 14TH 
WETTEST DAY ON RECORD. 

SURVEYING MONTHLY RAINFALL TOTALS, MARATHON'S MAY MEASUREMENT OF 
15.66 INCHES RANKS AS THE 5TH WETTEST MONTH ON RECORD, IN THE TOP 
ONE PERCENT OF ALL MONTHS, WITH 13.39 INCHES FOR OCTOBER PLACING 
11TH WETTEST. TWO ADDITIONAL MONTHS, JULY WITH 10.59 INCHES AND 
SEPTEMBER WITH 10.20 INCHES, ALSO RANK IN THE TOP 50 WETTEST MONTHS, 
27TH AND 33RD RESPECTIVELY. KEY WEST'S SEPTEMBER TOTAL OF 12.21 
INCHES PLACES AS THE 33RD WETTEST, OR IN THE TOP TWO PERCENT OF 
MONTHS ON RECORD.

THE TABLE BELOW BREAKS DOWN EACH CLIMATE SITE'S MONTHLY AND ANNUAL 
AVERAGE TEMPERATURE READING, THE DEPARTURE FROM NORMAL, AND HOW EACH 
MONTH RANKED AMONGST THE PERIOD OF RECORD.

AVERAGE TEMPERATURE READINGS, DEPARTURE FROM NORMAL, AND RANKINGS

LOCATION           KEY WEST           |          MARATHON
(RECORDS TO)        (1872)            |           (1950)
                                      |
          AVERAGE DEP FM RANK         | AVERAGE DEP FM RANK
PERIOD    (DEG F) NORMAL              | (DEG F) NORMAL
========= ======= ====== ============ | ======= ====== ============
JANUARY    72.7   +3.4                |  72.3   +2.7  
FEBRUARY   74.7   +3.7                |  74.6   +3.0   8TH  WARMEST
MARCH      77.4   +4.2   3RD* WARMEST |  78.1   +4.1   2ND  WARMEST   
APRIL      80.9   +4.5   WARMEST      |  82.9   +5.6   WARMEST
MAY        80.7   +0.4                |  80.9   -0.5   
JUNE       85.1   +1.8   3RD* WARMEST |  85.4   +0.6   6TH* WARMEST
JULY       85.9   +1.4   10TH*WARMEST |  85.1   +0.1   
AUGUST     87.2   +2.7   2ND  WARMEST |  86.1   +0.8   10TH WARMEST
SEPTEMBER  85.6   +2.4   2ND  WARMEST |  84.8   +0.9   7TH* WARMEST
OCTOBER    82.7   +2.5   5TH* WARMEST |  82.2   +1.5   9TH  WARMEST
NOVEMBER   77.8   +2.0                |  78.2   +2.4   4TH  WARMEST
DECEMBER   70.0   -1.4                |  70.0   -1.7   
---------  ----   ----   ------------ |  ----   ----   ------------
ANNUAL     80.1   +2.3   2ND  WARMEST |  80.1   +1.6   4TH  WARMEST

* INDICATES A TIED RANK


THE TABLE BELOW BREAKS DOWN EACH CLIMATE SITE'S MONTHLY AND ANNUAL 
RAINFALL TOTALS, THE DEPARTURE FROM NORMAL, AND HOW EACH MONTH 
RANKED AMONGST THE PERIOD OF RECORD.

MONTHLY/ANNUAL RAINFALL TOTAL, DEPARTURE FROM NORMAL, AND RANKING

LOCATION            KEY WEST          |          MARATHON
(RECORDS TO)         (1871)           |           (1950) 
------------------------------------- | --------------------------
           TOTAL  DEP FM RANK         | TOTAL  DEP FM RANK
PERIOD     (IN.)  NORMAL              | (IN.)  NORMAL     
=========  ====== ====== ============ | ====== ====== ============
JANUARY     1.30  -0.74               |  1.69   +0.08              
FEBRUARY    0.72  -0.77               |  1.26   -0.95              
MARCH       0.02  -2.03  6TH  DRIEST  |  0.06   -2.33  3RD DRIEST 
APRIL       0.72  -1.33               |  1.14   -1.24              
MAY         4.18  +1.18               | 15.66  +12.31  WETTEST
JUNE        7.61  +3.50               |  1.48   -4.13              
JULY        6.19  +2.64               | 10.59   +6.31  WETTEST
AUGUST      2.61  -2.77               |  1.78   -5.21  3RD DRIEST 
SEPTEMBER  12.21  +5.50  9TH  WETTEST | 10.20   +2.47  8TH WETTEST
OCTOBER     7.77  +2.84               | 13.39   +8.61  4TH WETTEST
NOVEMBER    7.52  +5.22  6TH  WETTEST |  6.33   +3.51  2ND WETTEST
DECEMBER    1.45  -0.77               |  0.97   -1.05  
---------  ----- ------  ------------ | -----  ------  -----------
ANNUAL     52.30 +12.47  14TH WETTEST | 64.55  +18.38  2ND WETTEST


THE TABLE BELOW BREAKS DOWN THE DAILY AND MONTHLY RECORDS SET OR 
TIED THROUGHOUT THE YEAR AT BOTH CLIMATE LOCATIONS.

RECORDS SET OR TIED AT KEY WEST AND MARATHON DURING 2020

RECORD                    KEY WEST  MARATHON
========================  ========  ========

DAILY RECORDS

MAXIMUM TEMPERATURE          12        21   
COOL MAXIMUM TEMPERATURE      1         1
WARM MINIMUM TEMPERATURE     73        30      
MINIMUM TEMPERATURE           0         0
RAINFALL                      6        10 

DAILY RECORDS SETTING/TYING MONTHLY RECORDS

MAXIMUM TEMPERATURE           0         0   
COOL MAXIMUM TEMPERATURE      0         0
WARM MINIMUM TEMPERATURE      5         0      
MINIMUM TEMPERATURE           0         0
RAINFALL                      1         1 


ANOTHER INTERESTING TIDBIT IS THAT BOTH CLIMATE SITES RECORDED THE 
SAME AVERAGE TEMPERATURE FOR THE YEAR, WHICH HAS ONLY OCCURRED TWICE 
IN THEIR OVERLAPPING PERIOD OF RECORD (IN 2010 AND 1972). MONTHLY 
AVERAGE TEMPERATURE TIES ARE A LITTLE MORE COMMON, WITH THE MOST 
RECENT TIE OCCURRING IN MAY 2014.

THE CURRENT KEY WEST CLIMATE LOCATION REFERENCED IS THE KEY WEST 
INTERNATIONAL AIRPORT ASOS, WITH RECORDS FOR THE KEY WEST AREA 
DATING BACK TO 1871. THE CURRENT MARATHON CLIMATE LOCATION 
REFERENCED IS THE FLORIDA KEYS MARATHON INTERNATIONAL AIRPORT ASOS, 
WITH RECORDS FOR THE MARATHON AREA DATING BACK TO 1950.

$$

ROSS/CHURCHILL

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