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

Highlights July 2013

New Records for July 2013

San Juan

Date New Record Previous Record
 July 2013  July 2013 ended as the wettest July on record with 14.17 inches of rain. This broke previous record of 11.23 inches of rain on July 1950. 
July 18th A 24hr rainfall of 9.23 inches of rain in the month of July. This broke previous record of 3.19 inches of rain set back in July 1950.
July 18th 2nd wettest day on record for any given day with 9.23 inches of rain. The wettest day on record for any given day continued to be August 15th, 1944 with 9.67 inches of rain.

Saint Croix   

Date New Record Previous Record
July 2013   July 2013 ended as the ninth driest July on record with 1.70 inches of rain. July 1976 continued to be the driest July on record with 0.49 inches of rain.  

Saint Thomas

Date New Record Previous Record
 July 28th A 24hr rainfall of 2.18 inches of rain in the month of July.   This broke previous record of 0.49 inches of rain set back in July 1958.  
July 2013 July 2013 ended as the ninth wettest July on record with 4.28 inches of rain. July 1958 continues to be the wettest July on record with 7.41 inches of rain.

July 2013 Statistics

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

  San Juan Saint Thomas Saint Croix
High 88.7°F 90.0°F 88.7°F
Low 78.1°F 78.0°F 78.5°F
Avg. T 83.4°F 84.0°F 83.6°F
Pcpn. 5.07’’ 2.85’’ 3.04’’

  July 2013 Observations:

  San Juan Saint Thomas Saint Croix
High 88.3°F(-0.4°F) 88.6°F(-1.4°F)
88.8°F(+0.1°F)
Low 77.4°F(-0.7°F) 78.2°F(+0.2°F) 77.8°F(-0.7°F)
Avg. T 82.8°F(-0.6°F) 83.4°F(-0.6°F) 83.3°F(-0.3°F)
Pcpn. 14.17" (+9.10") 4.28" (+1.43") 1.70" (-1.34")

July 2013 Extremes:

  San Juan Saint Thomas Saint Croix
High  93°F July 29th  92°F July 19th  91°F July 19th
Low  74°F July 18th and 3rd  75°F July 3rd  74°F July 29th

Monthly Summary 

    July 2013 turned out to be the wettest July on record in the San Juan Metro Area, and the ninth wettest at Cyril E. King Airport, Saint Thomas, which was indicative of continued deep moisture transport and general troughiness over the area. In addition to the aforementioned features, the first strong tropical wave of the 2013 Atlantic Hurricane Season to affect Puerto Rico and the US Virgin Islands brought heavy rainfall and cool temperatures to the region on July 18th. While widespread rainfall totals of 3 to 5 inches were observed across the eastern half of Puerto Rico during the tropical wave passage, the highest rainfall amounts were noted across the San Juan Metro Area with totals in excess of 9 inches. By the end of the month, the widespread heavy rains ended, and once again, shower and thunderstorm activity shifted to a more typical pattern, with areas of locally induced activity. 

 

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

July Historical Statistics              

Highest  July Temperatures on record:

San Juan Saint Thomas Saint Croix
95°F July 10th 1981  98°F July 27th 1994   94°F July 20th 1972
 94°F July 8th 1995 97°F July 24th 1994   94°F July 8th 1972
94°F July 1st 1995  97°F July 22nd 1994  93°F July 10th 2007 

Lowest July Temperatures on record: 

San Juan Saint Thomas Saint Croix
69 °F July 1st 1959 70°F July 28th 1994  64°F July 5th 1998 
69°F July 12th 1952  70°F July 13th 1980   67°F July 19th 1979
69°F July 11th 1952 70°F July 30th 1972  68°F July 22nd 1982 

Wettest Julys :

San Juan Saint Thomas Saint Croix
14.17"  2013  7.41"  1958   7.62"  1958
11.23"  1950  7.40"  2010  6.91"  1964
11.08"  2011  5.74"  2005 6.57"  2011 

Driest Julys :

San Juan Saint Thomas Saint Croix
 1.10"  1929  0.03"  2007  0.49"  1976
 1.12"  1974  0.24"  1956 0.95"  2009 
 1.41"  1947  0.74"  1994 1.09"  2009 

Decadal July Observations for San Juan, Puerto Rico

  2010-2013 2000’s 1990’s 1980’s 1970’s 1960’s
High 88.3°F 88.8°F 88.6°F 89.6°F 88.5°F 87.3°F
Low 77.6°F 77.4°F 76.7°F 77.2°F 77.4°F 75.5°F
Avg. T 82.9°F 83.1°F 82.7°F 83.4°F 83.0°F 81.4°F
Pcpn. 10.15" 5.24" 5.47’’ 3.84’’ 3.16’’ 6.05’’

Looking ahead toward the month of August

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

  San Juan Saint Thomas Saint Croix
High 89.2°F 90.2°F 89.2°F
Low 78.2°F 78.2°F 78.4°F
Avg. T 83.7°F 84.2°F 83.8°F
Pcpn. 5.46’’ 3.74’’ 3.15’’

Precipitation Outlook for August-September-October  (click here for details)

 ASO rainfall likely normal to above-normal across most of the region; fair chance of wet conditions in many places within the Antilles.

El Niño/Southern Oscillation (ENSO) Diagnostic Discussion  (click here for details)

ENSO neutral is favored into the Northern Hemisphere fall 2013.

Moon/Sun/Tide Data for the month of August 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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