August 2009 Climate Report for Puerto Rico and the U.S. Virgin Islands  

August 2009 Highlights:

 

Temperatures across Puerto Rico ranged from 56ºF in Adjuntas on the 17th of August to 97ºF in Ponce on the 10th of the month. Temperatures across the U.S. Virgin Islands ranged from 70ºF at Beth Upper New Works on Saint Croix, observed both on August 3rd & 30th, to 93ºF, recorded at the airports on Saint Thomas and Saint Croix, on the 7th & 8th of the month respectively. Other notable temperatures for August 2009 are listed below:
 

Other Notable August 2009 High Temps:      
 
96ºF in Aguadilla on August 30th   
95ºF in San Juan on August 26th  
95ºF at Dos Bocas on August 27th
94ºF in Aguirre Central, Mayaguez, Lajas,
             Guayama, and Gurabo.
 
Other Notable August 2009 Low Temps:
 
64ºF in Toro Negro on August 11th   
65ºF in Aibonito on August 18th    
65ºF in Maricao on August 25th   
67ºF in Lajas on August 17th    
67ºF in Arecibo on August 6th
 

 
The highest 24-hour precipitation total for the month of August was 3.02”, which fell in Toro Negro on the 11th of the month. The highest weekly rainfall total occurred in Rio Piedras, where 6.98” of rainfall accumulated the week ending August 7th. Across the U.S. Virgin Islands, the island of Saint Croix recorded its third driest August on record, making the first 8 months of the year the driest start on record across the island.

 Figure 1A – Island wide precipitation forJanuary-August2009

Figure 1B – Graphical Display of August 2009 precipitation across Puerto Rico and the U.S. Virgin Islands derived from a combination of rain gage and radar data.

 

Monthly Weather Summary:
 
 
August 2009 Statistics:
 
Average August Temperatures/Precipitation (NCDC 1971-2000 averages):
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.8ºF
77.0ºF    
82.4ºF
5.22”
Saint Thomas
90.8ºF    
77.7ºF    
84.3ºF
3.50”
Saint Croix
89.7ºF
77.9ºF
83.8ºF
3.81”

 
August 2009 Observations:
 

 
High:      
Low:     
AvgT:   
Pcpn:      
San Juan
89.9ºF     (+2.1ºF)
78.9ºF     (+1.9ºF) 
84.4ºF     (+2.0ºF) 
8.57”       (3.35”)  
Saint Thomas
89.9ºF     (-0.9ºF)  
79.6ºF     (+1.9ºF) 
84.7ºF     (+0.4ºF) 
1.76”       (-1.74”) 
Saint Croix
90.0ºF     (+0.3ºF)
78.7ºF     (+0.8ºF)
84.4ºF     (+0.6ºF)
1.66”       (-2.15”)

 
August 2009 Extremes:
 

 
High:  
Low:  
San Juan
95ºF – August 26th 
76ºF – August 29th
 
Saint Thomas
93ºF – August 7th & 14th  
76ºF – August 17th
Saint Croix
93ºF – August 8th   
75ºF – August 15th & 20th

 
August Historical Statistics:
 
Highest August Temperatures on record:
 

San Juan              
97ºF – August 21st, 1980
96ºF – August 10th, 1980*
*Most recent occurrence  
Saint Thomas      
99ºF – August 4th, 1994 & August 8th, 1979
98ºF – August 13th, 1994*
*Most recent occurrence
Saint Croix
95ºF – August 25th, 1999 & August 19th, 1972
94ºF – August 4th, 1972*
*Most recent occurrence

 
Lowest August Temperatures on record:
 

San Juan              
70ºF – August 24th & 26th, 1956
71ºF – August 23rd, 2000*
*Most recent occurrence
Saint Thomas
67ºF – August 12th, 1956
70ºF – August 18th, 1982*  
*Most recent occurrence
Saint Croix
63ºF – August 17th, 1978
67ºF – August 31st, 1979*
*Most recent occurrence

 
Wettest Augusts:
 

San Juan              
11.31” August 1988
9.52” August 2000
9.38” August 1979
Saint Thomas      
8.54” August 1963
8.22” August 2005
6.71” August 1955
Saint Croix
11.41” August 1979
11.04” August 1989
7.80” August 1978

 
Driest Augusts:
 

San Juan              
1.83” August 1994
1.93” August 1982
1.94” August 1991
Saint Thomas
0.70” August 1993
0.98” August 1991
1.26” August 2002
Saint Croix
1.35” August 2005
1.40” August 1980
1.51” August 2009

 

2000-2009 Decade in Review:

 
Decadal Observations for San Juan, Puerto Rico:
 
Decadal August High Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
89.0ºF
 
89.4ºF
 
89.9ºF
 
88.3ºF
 
87.8ºF
 
88.1ºF

 
Decadal August Low Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
77.6ºF
 
77.3ºF
 
77.0ºF
 
77.3ºF
 
75.6ºF
 
74.1ºF

 
Decadal August Average Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
83.3ºF
 
83.3ºF
 
83.4ºF
 
82.8ºF
 
81.6ºF
 
81.1ºF

 
Decadal August Precipitation:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
5.92”
 
4.83”
 
5.08”
 
5.27”
 
6.13”
 
6.45”

* Records for San Juan began on January 1st, 1956

 

 

 

 

 

Looking ahead toward the month of September:

 
Average September Temperatures/Precipitation (NCDC 1971-2000 averages):
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.8ºF
76.5ºF    
82.2ºF
5.60”
Saint Thomas
90.2ºF    
76.9ºF    
83.6ºF
5.57”
Saint Croix
89.2ºF
76.8ºF
83.0ºF
5.36”

 

 

Moon/Sun/Tide Data for the month of September:

 
                The sun rises at 6:10 am AST on the 1st of September and sets at 6:39 pm AST, in San Juan, Puerto Rico. This represents a total of 12 hours and 29 minutes of daylight. By September 30th, the sun will rise at 6:15 am AST and set at 6:14 pm AST, providing a total of 11 hours and 59 minutes of daylight, or a total decrease of 30 minutes over the course of the month. At Charlotte Amalie on Saint Thomas, the sun will rise at 6:05 am AST and set at 6:34 pm AST on the 1st of the month. By the end of the month, the sun will rise at 6:10 am AST and set at 6:09 pm AST, also representing a total decrease in daylight of 30 minutes for the month.
 
                For the month of September, a full moon will be observed on the 4th of the month at 12:03 pm AST. There will also be a new moon on the 18th of the month at 4:44 pm AST. The first quarter of the moon was observed on the 27th of August and the last quarter of the moon will be observed on the 11th of September.
 
                Links to additional sunrise/sunset data, phases of the moon, as well as tide data can all be found by clicking on the climate link of the National Weather Service San Juan homepage (www.srh.noaa.gov/sju) and then clicking on the Astronomical tab.

 


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