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 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
(Records to) |
KEY WEST
(1872) |
|
| |
MARATHON
(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.
LINKS:
NOAA/NWS Florida Keys:
[livemarket market_name="KONK Life LiveMarket" limit=3 category=“” show_signup=0 show_more=0]
No Comment