FLORIDA KEYS — 2020 was definitely all wet, in terms of both sweat and rainfall.
In fact, it was among the hottest and rainiest years on record, according to meteorologists William Churchill and David Ross from the National Weather Service in Key West, which recently reviewed temperature and rainfall data from the official stations in Key West and Marathon airports.
Last year’s average annual temperature of 80.1 degrees at both stations was 2.3 and 1.6 degrees, respectively, above the climatological normal value, which is based on a rolling 30-year average that currently spans from 1981 to 2010.
These averages also ranked in the top five for warmest years on record at both locations. It was the second warmest year at Key West and fourth 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 hot year was an abundance of warmer low temperatures. Between the two locations there were 103 daily warm minimum temperature records set or tied in 2020, with Key West recording more than two-thirds of them.
For low temperatures of 85 degrees or higher, 2020 also took the top spot with 24 such days — a 50% increase over the previous top spot of 16 days in 2007.
The National Weather Service also reported that Marathon measured 64.55 inches of rainfall last year, putting it 18.38 inches above normal and making it the second wettest year on record. Key West measured 52.30 inches of rainfall, which is 12.47 inches above normal, though not a record year.
Key West’s wettest day of the year, Sept. 12, recorded 9.37 inches of rainfall, making September the wettest month of 2020.
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 Florida Straits and sparking off a thunderstorm that produced 4 inches of rainfall in just one hour in Key West, according to the meterologists.
While Marathon’s wettest day was also Sept. 12, when 8.13 inches of rainfall was recorded, it only helped make September the fourth wettest month of the year with 10.20 inches of rainfall. Three additional months — May, July and October — topped the 10-inch mark, with 15.66, 10.59 and 13.39 inches of rainfall, respectively.
Not only did the Sept. 12 rainfall totals set new daily records for September at both locations, they also have the distinction of being some of the wettest days on record, the meteorologists reported. It marked the fifth wettest day ever for the Key West area and the third wettest for the Marathon area.