KEY WEST CLIMATE STATISTICS FOR 1998

 

TEMPERATURE

AVG. MONTHLY MAX. 82.7 F AVG. MONTHLY MIN. 73.7 F

DEPARTURE FROM NORMAL + 0.2 F DEPARTURE FROM NORMAL + 0.6 F

AVG. YEARLY TEMP. 78.4 F DEPARTURE FROM NORMAL: +0.6 F
 

HIGHEST MONTHLY AVG. TEMP: 85.8 F MONTH: JULY

LOWEST MONTHLY AVG. TEMP.: 70.6 F MONTH: MARCH
 

AVERAGE MONTHLY TEMPERATURE...

LARGEST POSITIVE DEPARTURE FROM NORMAL: 3.5 F MONTH: DECEMBER

" NEGATIVE " " " : 3.2 F MONTH: MARCH
 

HIGHEST TEMP.: 93 F DATE: 7/4 LOWEST TEMP.: 54 F DATE: 3/4

PRECIPITATION

TOTAL: 37.95 INCHES DEPARTURE FROM NORMAL: - 1.64 INCHES
 

GREATEST 24 HOUR RAINFALL: 8.38 INCHES DATE: SEPTEMBER 25

GREATEST MONTHLY RAINFALL: 11.63 INCHES MONTH: SEPTEMBER

LEAST MONTHLY RAINFALL: 0.86 INCHES MONTH: MAY AND JUNE
 

LARGEST POSITIVE DEPARTURE FROM NORMAL: 5.78 MONTH: SEPTEMBER

" NEGATIVE " " " : 4.23 MONTH: JUNE

NUMBER OF DAYS WITH...

PRECIP. > 0.01 INCHES: 100 (106 NORMAL)

PRECIP. > 0.10 INCHES: 54

PRECIP. > 0.50 INCHES: 21

PRECIP. > 1.00 INCHES: 8 ( 10 NORMAL)

THUNDERSTORMS: 64 (64 NORMAL)

FOG (VIS. < 6 MILES): 89

FOG REDCUING VIS. TO 1/4 MILE OR LESS: 5 (1.2 NORMAL)

SMOKE/HAZE: 43

WATERSPOUTS: 26

MAX. TEMPS. > 90 F: 73 (40 NORMAL)

COLD FRONTAL PASSAGES: 21 (JAN AND FEB WITH 5 EACH)

TROP. CYCLONES PASSING WITHIN A 50 MILE RADIUS OF EYW: 2


MISCELLANEOUS

HIGHEST BAROMETRIC PRESSURE: 30.44 INCHES 01/01

LOWEST BAROMETRIC PRESSURE: 28.94 INCHES 9/25

HEATING DEGREE DAYS: 38 DEPARTURE: -62

COOLING DEGREE DAYS: 4,930 DEPARTURE: +42

PEAK WIND/DIRECTION: 105 MPH/SE DATE: 9/25 (AT NAS BOCA CHICA)

HIGHEST SUSTAINED WIND/DIR: 92 MPH/SE DATE: 9/25 (AT NAS BOCA CHICA)

HIGHEST AVERAGE DAILY WIND SPEED: NA MPH DATE: 9/25


RECORDS

RECORDS SET OR TIED
 
JANUARY: 15TH, SET DAILY RAINFALL RECORD OF 1.67 INCHES
 

FEBRUARY: 2ND, SET DAILY RAINFALL RECORD OF 2.34 INCHES

2ND, SET HIGHEST SUSTAINED WIND AND PEAK GUST FOR THE MONTH OF FEBRUARY AT 57 MPH FROM SE AND 68 MPH FROM SE RESPECTIVELY.
 

MARCH: 11th, TIED RECORD LOW MAXIMUM TEMPERATURE FOR THE DAY WITH A MAX. OF 63 F.

12th, TIED RECORD LOW MINIMUM AND MAXIMUM TEMPERATURE FOR THE DAY WITH A MINIMUM OF 56 F AND MAXIMUM OF 65 F.
 

APRIL: 9TH, TIED RECORD HIGH MINIMUM TEMPERATURE FOR DAY WITH A MINIMUM TEMPERATURE OF 77 F

24TH, SET RECORD MINIMUM TEMPERATURE FOR DAY WITH A LOW OF 63 F
 

JUNE: 6TH, 9TH, 16TH, 17TH, 19TH, 22ND, 25TH, TIED RECORD HIGH MINIMUM TEMPERATURES FOR EACH DAY WITH MINIMUMS OF 82 F, 84 F, 83 F,

83 F, 83 F, 83 F, 84 F RESPECTIVELY.
 

JULY: 7TH, SET RECORD HIGH MINIMUM TEMPERATURE FOR DAY AT 84 F.
 

SEPTEMBER: 7TH, 11TH, TIED RECORD HIGH MINIMUM TEMPERATURES FOR EACH DAY WITH 83 F AND 83 F
 

25TH, SET RECORD HIGHEST SUSTAINED WIND AND PEAK GUST FOR MONTH OF SEPTEMBER AND ALL TIME WITH 92 MPH FROM SE AND 105 MPH FROM SE. WINDS WERE OBSERVED AT NAS BOCA CHICA DURING HURRICANE GEORGES. KEY WEST EQUIPMENT FAILED DURING HURRICANE AND IT WAS ESTIMATED TO BE THE SAME ON KEY WEST. WIND RECORDS ARE ONLY AVAILABLE FOR APPROXIMATELY 20 YEARS. THERE MAY HAVE BEEN HIGHER WINDS IN KEY WEST DURING ANOTHER HURRICANE BUT THERE IS NO RECORD OF IT.
 

ALSO ON 25TH, SET DAILY AND MAXIMUM 24 HOUR RAINFALL RECORD FOR SEPTEMBER WITH 8.38 INCHES OF RAIN.
 

OCTOBER: 6TH, TIED RECORD HIGH MINIMUM TEMPERATURE WITH 82 F
 

DECEMBER: 13TH, TIED RECORD HIGH MINIMUM TEMPERATURE WITH 76 F


SIGNIFICANT WEATHER EVENTS

FEBRUARY 2ND: VERY STRONG LOW DEVELOPED IN SE GULF OF MEXICO AND MOVED NORTHEAST THROUGH CENTRAL FL. COLD FRONT MOVED THROUGH KEYS. SQUALL LINE AHEAD OF COLD FRONT PRODUCED WIDESPREAD SUSTAINED WINDS OF 50 TO 70 MPH. MAXIMUM SUSTAINED WIND AT KEY WEST WAS 55 MPH FROM SE. SEVERAL PLACES HAD WIND GUSTS TO NEAR 90 MPH. THE LONG KEY C-MAN STATION JUST NORTH OF LONG KEY RECORDED A 119 MPH WIND GUST FROM SE. MAXIMUM WIND GUST AT KEY WEST WAS 68 MPH FROM SE. GOLFBALL SIZED HAIL WAS REPORTED IN MARATHON. AN F1 TORNADO WENT THROUGH GRASSY KEY CAUSING SIGNIFICANT DAMAGE AND SOME INJURIES. AN FO TORNADO MOVED THROUGH ISLAMORADA CAUSING SOME MINOR DAMAGE. WIDESPREAD COASTAL FLOODING AND POWER OUTAGES ALSO OCCURRED WITH THIS STORM.
 

JUNE 18TH: A WATERSPOUT FORMED NEAR A THUNDERSHOWER JUST NORTH OF KEY WEST AND MOVED SOUTH ONSHORE ALONG NORTH ROOSEVELT BOULEVARD IN KEY WEST. MINOR DAMAGE OCCURRED AT SCOTTY'S HARDWARE STORE, THE OVERSEAS MARKET, AND SOME CARS AND HOMES ALONG FLAGLER AVENUE. WHEN A WATERSPOUT MOVES ONSHORE, IT IS CONSIDERED A TORNADO. THIS IS THE 3RD TORNADO TO HIT THE KEYS IN 1998.
 

JULY 4TH: A SEVERE THUNDERSTORM MOVED SOUTH FROM THE EVERGLADES ACROSS THE FLORIDA BAY AND THROUGH MARATHON. THE THUNDERSTORM PRODUCED WIND GUSTS TO 60 TO 70 MPH, CAPSIZING A RECREATIONAL SAILBOAT A FEW MILES SOUTH OF MARATHON. FIVE PEOPLE WERE THROWN OVERBOARD AND 1 MAN DROWNED. THE 4 THAT WERE RESCUED ALL WORE LIFE JACKETS.
 

SEPTEMBER 24TH: THIS WAS THE LAST DAY OF 1998 WITH MAXIMUM TEMPERATURES AT 90 F OR HIGHER AND IT MADE THE 73RD DAY OF 1998 WITH MAXIMUM TEMPERATURES 90 F OR GREATER IN KEY WEST. THIS IS COMPARED TO THE NORMAL OF 40 SUCH DAYS.
 

SEPTEMBER 25TH: THE EYE OF HURRICANE GEORGES MOVES TOWARD THE WEST-NORTHWEST ACROSS THE FLORIDA STRAITS, PASSING A FEW MILES SOUTH OF KEY WEST. GEORGES WAS A WEAK CATEGORY 2 STORM WHEN IT AFFECTED THE KEYS. SEE THE REPORT ON THE EFFECTS ON THE KEYS FROM HURRICANE GEORGES ON THE FIRST PAGE OF THE NWSO KEY WEST WEBSITE.
 

NOVEMBER 4TH: TROPICAL STORM MITCH MOVED ACROSS THE SOUTHERN GULF OF MEXICO JUST NORTH OF THE FLORIDA KEYS MAKING LANDFALL NEAR NAPLES, FLORIDA. MITCH PRODUCED SEVERE THUNDERSTORMS ACROSS THE ENTIRE KEYS WITH THE UPPER KEYS RECEIVING THE MOST DAMAGE. THERE WERE 3 TORNADO TOUCHDOWNS IN THE UPPER KEYS WITH AN F0 IN ISLAMORADA, F1 IN ROCK HARBOR, AND AN F2 IN KEY LARGO. THE KEY LARGO TORNADO CAUSED SIGNIFICANT DAMAGE AND INJURED 20 PEOPLE. THIS MADE 6 TORNADO TOUCHDOWNS IN THE KEYS FOR 1998. THIS IS A SIGNIFICANT ANOMALY CONSIDERING THE KEYS ONLY AVERAGE 2 TORNADO TOUCHDOWNS EVERY 3 YEARS SINCE 1950.


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