May 2012 Climate Report

May 2012 Climate Report for Puerto Rico and the U.S. Virgin Islands

May 2012 Highlights

New Records for May 2012

Date	New Record	Old Record
May 2nd	A daily maximum rainfall of 0.69"	This broke the old record of 0.66" set back in 2010.
May 17th	A daily maximum rainfall of 2.16".	This broke the old record of 1.42" set back in 1981.
May 2012	Eight wettest May on record with 6.72''	May 1960 ended as the wettest may on record with 16.39".
May 2012	Eleventh coolest May on record with an average temperature of 80.6°F.	May 1959 ended as the coolest May on record with an average temperature of 79.3°F

Saint Croix

Date	New Record	Old Record
May 26th	A record low temperature of 72°F.	This tied the old record of 72°F set back in 1983.
May 2012	Eleventh coolest May on record with an average temperature of 80.1°F.	May 1982 ended as the coolest May on record with an average temperature of 76.8°F

Other notable temperatures and precipitation amounts

Notable May 2012 High's	Notable May 2012 Low's
94°F May 31st Rio Piedras AES	57°F May 6th Cerro Maravilla
92°F May 24th Levittown	57°F May 29th Toro Negro

	Puerto Rico	Virgin Islands
Highest 24 hr Precip Total	5.1" May 7th Morovis	2.16" May 17th Saint Thomas
Highest Weekly Rainfall Accum.	6.97" May 13th-May 18th Trujillo Alto	3.64" May 5th-May 11th Fort Christiansted

May 2012 Statistics

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

	San Juan	Saint Thomas	Saint Croix
High	87.5°F	87.6°F	86.7°F
Low	76.3°F	76.2°F	76.1°F
Avg. T	81.9°F	81.9°F	81.4°F
Pcpn.	5.90’’	3.06’’	4.15’’

May 2012 Observations:

	San Juan	Saint Thomas	Saint Croix
High	86.7°F(-0.8°F)	85.3°F(-2.3°F)	85.4°F(-1.3°F)
Low	76.1°F(-0.2°F)	75.9°F(-0.3°F)	74.9°F(-1.2°F)
Avg. T	81.4°F(-0.5°F)	80.6°F(-1.3°F)	80.1°F(-1.3°F)
Pcpn.	5.28"(-0.62")	6.72"(+3.66")	3.69"(-0.46')

May 2012 extremes:

	San Juan	Saint Thomas	Saint Croix
High	91°F May 30th	87°F May 25th, 21st and 11th	87°F May 31st, 30th and 1st
Low	73°F May 4th	73°F May 2nd	72°F May 26th

Monthly Summary

May 2012 began with an upper level trough combined with a surface trough and deep tropical moisture to produce scattered showers and isolated thunderstorms across the local area during the first week of the month. Days after, a normal pattern prevailed across the area with afternoon showers and thunderstorms across the interior and western portions of Puerto Rico. Around the 20th, a high pressure ridge established across the area, and brought fair and mainly dry weather conditions across the islands. This tranquil weather pattern prevailed until the last week of the month, when a bit wetter pattern returns once again across the forecast area.

Rainfall Accumulations Year to Date (YTD)

Figure A – Graphical Display of May 2012 precipitation across Puerto Rico and the U.S. Virgin Islands derived from a combination of rain gage and radar data.

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

Sector

Rain YTD

Normal YTD

PON YTD

X North Coast

29.62

20.83

142%

X South Coast

15.25

8.11

188%

X North Slopes

26.38

20.78

127%

X South Slopes

17.45

16.10

108%

X East Interior

35.81

24.99

143%

X West Interior

35.26

25.62

138%

Puerto Rico Average

26.63

19.41

137%

X U.S. Virgin Islands

13.70

11.94

115%

PON= Percent of Normal YTD= Year to Date

  Figure C – Display of YTD precipitation by climate sectors derived from rain gage data.

May Historical Statistics

Highest May Temperatures on record:

San Juan	Saint Thomas	Saint Croix
96°F May 11th, 1980	97°F May 23rd, 1996	94°F May 28th, 1972
96°F May 5th, 1980	97°F May 19th, 1995	93°F May 25th, 1994
95°F May 21st, 2005	97°F May 7th, 1994	93°F May 30th, 1972

Lowest May Temperatures on record:

San Juan	Saint Thomas	Saint Croix
66°F May 5th, 1962	66°F May 5th, 1974	65°F May 8th, 1982
66°F May 3rd, 1903	68°F May 11th, 1986	65°F May 7th, 1982
67°F May 6th, 1962	68°F May 7th, 1986	65°F May 2nd, 1975

Wettest Mays:

San Juan	Saint Thomas	Saint Croix
16.88" 1936	16.39" 1960	14.03" 1981
14.99" 1965	9.98" 1979	11.38" 2001
13.97" 1902	9.80" 1987	8.89" 1987

Driest Mays:

San Juan	Saint Thomas	Saint Croix
0.44" 1972	0.06" 2008	0.22" 1974
0.48" 1973	0.28" 2007	0.28" 2005
0.71" 1925	0.47" 1973	0.37" 2003

Decadal May Observations for San Juan, Puerto Rico

	2010-2012	2000’s	1990’s	1980’s	1970’s	1960’s
High	86.2°F	87.4°F	87.8°F	88.2°F	87.4°F	86.0°F
Low	75.9°F	75.6°F	75.4°F	75.0°F	75.0°F	73.2°F
Avg. T	81.1°F	81.5°F	81.6°F	81.6°F	81.2°F	79.6°F
Pcpn.	9.56"	5.02’’	4.35’’	7.59’’	4.25’’	6.41’’

Looking ahead toward the month of June

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

	San Juan	Saint Thomas	Saint Croix
High	88.9°F	89.3°F	87.9°F
Low	77.7°F	77.7°F	78.1°F
Avg. T	83.3°F	83.5°F	83.0°F
Pcpn.	4.41’’	2.53’’	2.31’’

Moon/Sun/Tide Data for the Month of June 2012

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.

Click here to return to NWS San Juan Local Climate Web Page

Sector	Rain YTD	Normal YTD	PON YTD

X North Coast	29.62	20.83	142%
X South Coast	15.25	8.11	188%
X North Slopes	26.38	20.78	127%
X South Slopes	17.45	16.10	108%
X East Interior	35.81	24.99	143%
X West Interior	35.26	25.62	138%
Puerto Rico Average	26.63	19.41	137%
X U.S. Virgin Islands	13.70	11.94	115%

National Weather Service Weather Forecast Office