September 2013 Climate Report for Puerto Rico and the U.S. Virgin Islands

Highlights September 2013

New Records for September 2013

San Juan

Date New Record Previous Record
September 9th  A record high temperature of 94°F.   This tied the old record of 94°F set back in 1999.
September 14th A daily maximum rainfall of 2.88 inches. This broke the old record of 1.98 inches set back in 1928.
September 19th A record high temperature of 95°F.  This broke the old record of 93°F set back in 1995.
September 22nd A record high temperature of 94°F. This tied the old record of 94°F set back in 1999.
September 27th A record high temperature of 94°F.  This broke the old record of 93°F set back in 1978.
September 28th A record high temperature of 95°F. This tied the old record of 95°F set back in 1978.
September 29th A record high temperature of 96°F. This broke the old record of 94°F set back in 2001.
September 2013 September 2013 ended as the 5th warmest September on record with an average temperature of 84.4°F. September 2013 continues to be the warmest September on record with an average temperature of 84.9°F.

Saint Thomas

Date New Record Previous Record
 September 2013 September 2013 ended as the 6th wettest September on record with 9.82 inches.  September 1953 continues to be the wettest September on record with 14.94 inches.  

Saint Croix

Date New Record Previous Record
September 30th A record high temperature of 91°F. This tied the old record of 91°F set back in 1993.

September 2013 Statistics

 Average September Temperatures/Precipitation (NCDC 1981-2010 averages):

  San Juan Saint Thomas Saint Croix
High 89.2°F 90.0°F 89.0°F
Low 77.8°F 77.9°F 77.3°F
Avg. T 83.5°F 84.0°F 83.1°F
Pcpn. 5.77’’ 5.58’’ 4.86’’

  September 2013 Observations:

  San Juan Saint Thomas Saint Croix
High 90.4°F(+1.2°F) 88.5°F(-1.5°F)
88.7°F(-0.3°F)
Low 78.4°F(+0.6°F) 79.3°F(+1.4°F) 77.5°F(+0.2°F)
Avg. T 84.4°F(+0.9°F) 83.9°F(-0.1°F) 83.1°F(0.0°F)
Pcpn. 7.61" (+1.84") 9.82" (+4.24") 5.43" (+0.57")

September 2013 Extremes:

  San Juan Saint Thomas Saint Croix
High 96°F September 29th  91°F September 3rd and 2nd   91°F September 30th, 29th and 2nd
Low  74°F September 6th  74°F September 8th  75°F September 5th

Monthly Summary 

     Cloudiness and moderate to heavy rainfall associated with tropical storm Gabrielle affected the local area the first week of the month. Rainfall accumulations associated with Gabrielle were between 6 to 8 inches across USVI and eastern Puerto Rico during a 48 hour period. After the passage of Gabrielle over the Mona Passage, a generally fair and mainly dry weather pattern prevailed across Puerto Rico and USVI with warm to hot temperatures focused over the northern slopes of Puerto Rico. The aforementioned warm to hot temperatures were the result of a southerly wind flow that prevailed across the forecast area the last week of the month.

Rainfall Accumulation     

 

Figure A – Graphical Display of precipitation for September 2013 across Puerto Rico and the U.S. Virgin Islands derived from a combination of USGS rain gage sensors and radar data.

  

Climate Division Monthly Rain Normal Rain PON Rain YTD Normal Rain PON
North Coastal 6.27" 7.32" 86% 60.24" 45.85" 131%
South Coastal 7.15" 5.84" 122% 23.04" 27.59" 84%
Northern Slopes 2.89" 6.64" 43% 44.91" 39.68" 106%
Southern Slopes 11.47" 8.29" 138% 39.96" 37.14" 108%
Eastern Interior 8.41" 9.87" 85% 63.03" 56.78" 111%
Western Interior 8.73" 10.77" 81% 62.29" 56.96" 109%
Saint Thomas & Saint John 4.67" 5.34" 87% 30.11" 33.01" 91%
Saint Croix 4.57" 4.97" 92% 31.06" 25.51" 122%

 Figure B – Tabular Display of precipitation per climate zones for September 2013 across Puerto Rico and the U.S. Virgin Islands derived from COOP stations.

PON -Percent of Normal Precipitation YTD- Year to Date

 September Historical Statistics              

Highest September Temperatures on record:

San Juan Saint Thomas Saint Croix
 97°F September 1st 1981 98°F September 28th 1993  95°F September 14th 1983 
96°F September 18th 1995   98°F September 5th 1993  95°F September 25th 1972
96°F September 26th 1987  98°F September 1st 1993   95°F September 18th 1972

Lowest September Temperatures on record: 

San Juan Saint Thomas Saint Croix
 69°F September 15th 1960 64°F September 17th 1972  63°F September 5th 1979 
69°F September 6th 1960   66°F September 16th 1972  65°F September 8th 1982
 69°F September 16th 1929 68°F September 11th 1994   65°F September 25th 1975

Wettest Septembers:

San Juan Saint Thomas Saint Croix
15.17"   1996  14.94"   1953  19.16"   1996 
14.83"   1989  13.89"   2004  9.80"   1953 
13.68"   1928   12.86"   2008 9.03"   1954 

Driest Septembers:

San Juan Saint Thomas Saint Croix
 1.49"   1940   0.93"   2012   1.08"   1981
1.74"   1987   1.09"   1986  1.65"   2001
 1.78"   2006  1.42"   1987 1.96"   1986 

Decadal September Observations for San Juan, Puerto Rico

  2010-2013 2000’s 1990’s 1980’s 1970’s 1960’s
High 89.4°F 89.2°F 89.3°F 89.9°F 88.4°F 87.8°F
Low 78.1°F 77.2°F 76.9°F 76.6°F 76.9°F 74.9°F
Avg. T 83.8°F 83.2°F 83.1°F 83.2°F 82.7°F 81.4°F
Pcpn. 6.30" 5.86" 6.44’’ 4.61’’ 6.02’’ 5.83’’

Looking ahead toward the month of October

Normal Precipitation (click on the image to enlarge)

 Normal Temperatures

Maximum Temperatures Minimum Temperatures

Caribbean Climate Outlook for October-November-December (click here to details) 

 OND rainfall likely above- to normal across the region except in the north-west where below- to normal is expected; fair chance of wet conditions from Anguilla southward into Trinidad. Note the low predictability in many areas north of 16ºN and over the Guianas.

 Moon/Sun/Tide Data for the month of October 2013

Sunrise/sunset data, phase of the moon, as well as tide data can all be found by going to the climate portion of the National Weather Service San Juan Climate homepage and then clicking on the astronomical tab  


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