June 2010 Climate Report for Puerto Rico and the U.S. Virgin Islands

 

June 2010 Highlights:

 

 Temperatures across Puerto Rico ranged from 57ºF in Adjuntas on the 6th of June to 96ºF in both Borinquen and Gurabo on June 27th and 28th respectively. Temperatures across the U.S. Virgin Islands ranged from 73ºF, June 25th at Christiansted Airport on Saint Croix, to 94ºF, recorded at the Cyril E. King Airport on Saint Thomas June 16th. Other notable temperatures for June 2010 are listed below:

 
Other Notable June 2010 High’s:
 
95ºF in Lajas on June 20th
94ºF in Ponce on June 13th
94ºF in Juncos on June 13th   
93ºF at Dos Bocas on June 11th
93ºF at Guayama on June 19th
92ºF in San Juan and Trujillo Alto
Other Notable June 2010 Low’s:
 
64ºF in Aibonito on June 26th 
65ºF in Toro Negro on June 28th    
66ºF in Maricao on June 28th    
67ºF in Arecibo on June 14th   
67ºF in Ponce on June20th
67ºF in Lajas on June 16th
*If multiple occurrences, all dates above reflect the latest occurrence of the month.
 
The highest 24-hour precipitation total across Puerto Rico for the month of June was 5.11”, which fell in Trujillo Alto over the 24 hour period ending at 8am June 15th. The highest weekly rainfall across Puerto Rico occurred in San Lorenzo, where 10.55” of rain accumulated the week ending June 25th. Across the U.S. Virgin Islands, the highest 24-hour precipitation total fell at the Christiansted Airport on Saint Croix, where a record 3.94” fell over the 24 hour period ending at midnight on June 20th. For the week ending June 25th, 6.91” of rain fell at the Cyril E. King Airport on Saint Thomas, representing the highest weekly rainfall across the U.S. Virgin Islands for the month of June.

 

 Graphical display of precipitation across Puerto Rico from January 2nd, 2010 through July 2nd, 2010

Figure 1A – Island wide averaged precipitation (and normals) - by week - for the weeks beginning on January 2nd and ending on July 2nd, 2010

 

 June 2010 Rainfall composite using Radar and Rain Gage Data

Figure 1B – Graphical Display of June 2010 precipitation across Puerto Rico and the U.S. Virgin Islands derived from a combination of rain gage and radar data.

 

Monthly Weather Summary: 

 

June 2010 began with hazy skies and limited shower activity across the local islands as a result of an upper level ridge and Saharan air moving across the region. This fair weather pattern across the local region prevailed through June 3rd, when an upper level disturbance and a low level trough increased shower and thunderstorm activity across Puerto Rico and the U.S. Virgin Islands. Afterwards, a serial of tropical waves began to approach the regional waters. After June 8th, tropical waves and upper level troughs dominated the weather pattern, producing widespread showers and thunderstorms across the local islands. By the end of the month, the widespread heavy rains dried out, and shower and thunderstorm activity shifted to a more typical pattern of daily activity confined mostly to western portions of Puerto Rico.

Normally, June is a transition between the wet month of May, and the drier weather typically observed before the peak of hurricane season. This was not the case in 2010. Statistically, June 2010 was well above normal, in terms of precipitation.  At the Luis Muñoz Marin International Airport in San Juan, the monthly precipitation total was nearly half a foot above normal (5.71”), which accounted for the 6th wettest June on record. Across the U.S. Virgin Islands, precipitation was also well above normal, with the wettest June on record occurring at the Cyril E. King Airport on Saint Thomas and the second wettest June on record occurring at the Christiansted Airport on Saint Croix.

In terms of temperature, 2010 has been an unusually warm year across the northeastern Caribbean, with the average temperature in San Juan running approximately one degree above normal every single month of 2010. The highest monthly temperature in San Juan was 92 degrees on June 7th, and the low temperature fell to 74 degrees on both June 20th and June 23rd. At the end of the month, the average temperature was 0.6 degrees above normal, which marked the 13th consecutive month of above normal temperatures in San Juan.

 

June 2010 Statistics: 

 
Average June Temperatures/Precipitation (NCDC 1971-2000 averages):
 
 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.6ºF
76.6ºF   
82.1ºF
3.52”
Saint Thomas
89.5 ºF  
77.4ºF   
83.5ºF
2.35”
Saint Croix
88.6ºF
78.1ºF
83.4ºF
2.30”
 
June 2010 Observations:
 
 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan
87.8ºF    (+0.2ºF)
77.5ºF    (+0.9ºF)
82.7ºF    (+0.6ºF)
9.23”      (+5.71”)
Saint Thomas
88.3ºF    (-1.2ºF) 
79.4ºF    (+2.0ºF)
83.8ºF    (+0.3ºF)
9.51”      (+7.16”)
Saint Croix
88.4ºF    (-0.2ºF)
78.0ºF    (-0.1ºF)
83.2ºF    (-0.2ºF)
7.03”      (+2.38”)
 
June 2010 Extremes:
 
 
High:  
Low:  
San Juan
92ºF – June3rd & 7th
74ºF – June 20th & 23rd    
Saint Thomas
94ºF – June16th     
75ºF – June 20th & 25th
Saint Croix
92ºF – June 9th  
73ºF – June 23rd & 25th  

June Historical Statistics:   

 

Highest June Temperatures on record:
 

San Juan              
97ºF – June 5th, 1988 & June 22nd, 23rd & 25th, 1983
96ºF – June 27th, 1988*
*Most recent occurrence  
Saint Thomas      
99ºF – June 23rd, 1996
98ºF – June 29th, 1980*
*Most recent occurrence
Saint Croix
97ºF – June 18th, 1993
95ºF – June 24th, 1972
94ºF – June 2nd, 1972

 
Lowest June Temperatures on record:
 

San Juan              
69ºF – June 1st, 1957 & June 20th, 1956
70ºF – June 6th, 1964*
*Most recent occurrence
Saint Thomas
67ºF – June 20th & 21st, 1972
68ºF – June 1st, 1974
69ºF – June 22nd, 1981*
*Most recent occurrence
Saint Croix
66ºF – June 28th, 1979
67ºF – June 12th, 1954
68ºF – June 26th, 1953

 
Wettest Junes:
 

San Juan              
10.96” June 1965
10.37” June 2009
9.32” June 1958
Saint Thomas      
9.51” June 1960
8.29” June 1956
6.97” June 1983
Saint Croix
7.83”  June 1987
7.03”  June 2010
6.34”  June 1979

 
Driest Junes:
 

San Juan              
0.29” June 1985
0.98” June 1997
1.24” June 1971
Saint Thomas
0.07” June 2007
0.18” June 2003
0.28” June 1989
Saint Croix
0.10” June 2001
0.12” June 1985
0.49” June 2003
 

 

2000-2010 Decade in Review:

 

 

                June 2010 marked the 13th consecutive month of above normal temperatures in San Juan. June 2010 was also the 6th wettest June on record in San Juan and ranked as the wettest June on record at Cyril E. King Airport on Saint Thomas and the second wettest at the Christiansted Airport on Saint Croix. This was in large part due to a very strong early season tropical wave that broke numerous precipitation records across Puerto Rico and the US Virgin Islands during the middle of the month. In fact, 2010 has generally been a very wet year to date across Puerto Rico, so far ranking as the wettest start to a year since record keeping began in San Juan. For a look at temperature and precipitation deviations for San Juan, Saint Thomas and Saint Croix from their NCDC averages, see Figures 2 to 6 below. A summary of June 2010 data for San Juan along with the previous 6 decades of data from San Juan has also been included below.

 

 

Decadal Observations for San Juan, Puerto Rico:      

 

Decadal June High Temperatures:

2010
2000’s
1990’s
1980’s
1970’s
1960’s
1950’s
87.8ºF
88.9ºF
88.9ºF
89.7ºF
88.6ºF
87.4ºF
87.3ºF

 
 
Decadal June Low Temperatures:

2010
2000’s
1990’s
1980’s
1970’s
1960’s
1950’s
77.5ºF
77.0ºF
76.7ºF
76.6ºF
76.8ºF
74.5ºF
73.3ºF

 
Decadal June Average Temperatures:

2010
2000’s
1990’s
1980’s
1970’s
1960’s
1950’s
82.7ºF
83.0ºF
82.8ºF
83.2ºF
82.7ºF
80.9ºF
80.3ºF

 
 
Decadal June Precipitation:

2010
2000’s
1990’s
1980’s
1970’s
1960’s
1950’s
9.23”
4.71”
4.30”
3.41”
3.48”
5.27”
7.04”

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

 

  

San Juan Temperature deviations for the month of June since 2000

Figure 2 - Temperature deviations for San Juan, PR

 Saint Thomas USVI temperature deviations for the month of June since 2000

Figure 3 - Temperature deviations for Saint Thomas, VI

 Saint Croix USVI temperature deviations for the month of June since 2000

Figure 4 - Temperature deviations for Saint Croix, VI

 Precipitation deviations for the USVI and San Juan, PR for the month of June since 2000

Figure 5 - June 2000's precipitation deviations from normal

 Year to date percent of normal precipitation for San Juan, PR and the USVI

 Figure 6 - January - June 2010 precipitation deviations for San Juan, Saint Thomas, and Saint Croix 

 

Looking ahead toward the month of July: 

Looking ahead, July is the 6th driest month across Puerto Rico, with the Luis Muñoz International Airport in San Juan receiving 4.16” of rainfall on average. A record 9.35” of rain fell in July 1961 and the driest July on record was July 1974, when only 1.12” of rainfall was recorded in San Juan. The average high temperature at the Luis Muñoz International Airport in San Juan for July is 82.2 ºF, making July the 2nd warmest month of the year, second only to August. Presently, we are experiencing ENSO-neutral conditions with a La Niña Watch now in effect. 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf 
 
This transition has an impact on expectations for the hurricane season, with NOAA currently forecasting a 95% of a near or above normally active hurricane season.
 
Average July Temperatures/Precipitation (NCDC 1971-2000 averages):
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.4ºF
76.9ºF   
82.2ºF
4.16”
Saint Thomas
90.4ºF   
77.8ºF   
84.1ºF
2.42”
Saint Croix
89.3ºF
78.0ºF
83.7ºF
2.79”
 

 

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

 

 

                The sun rises at 5:52 am AST and sets at 7:05 pm AST, in San Juan, Puerto Rico on July 1st. This represents a total of 13 hours and 13 minutes of daylight. By July 31st, the sun will rise at 6:02 am AST and set at 7:00 pm AST, providing a total of 12 hours and 58 minutes of daylight, or a total decrease in 15 minutes over the course of the month.
 
At Charlotte Amalie on Saint Thomas, the sun will rise at 5:47 am AST and set at 7:00 pm AST on the 1st of the month. By the end of the month, the sun will rise at 5:57 am AST and set at 6:55 pm AST, representing a total decrease in daylight of 15 minutes over the course of the month.
 
                For the month of July, a full moon will be observed on the 25th of the month at 9:37 pm AST. There will also be a new moon on the 11th of the month at 3:40 pm AST. The last quarter of the moon will be observed on the 4th of July and the first quarter of the new moon will be observed on the 18th of the month.
 
                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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