September 2012 Climate Report

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

September 2012 Highlights

New Records for September 2012

Date	New Record	Previous Record
September 15th	A record high temperature of 92°F.	This tied the previous record of 92°F set back in 2003 and 1978.
September 2012	September 2012 ended as the sixth driest September on record with 2.13 inches.	The driest September on record is September 1940 with1.49 inches.
September 2012	September 2012 ended as the warmest September on record with an average temperature of 84.9°F	This tied the previous record of 84.9°F set back in September 1995.
September 2012	September 2012 ended as the fifth hottest month of any year with an average temperature of 84.9°F.	The hottest month ever was June 2012 with an average temperature of 85.7°F.

Saint Thomas

Date	New Record	Previous Record
September 2012	September 2012 ended as the driest September on record with 0.92 inches.	This broke the previous record of 1.08 inches set back in September 1986.

Saint Croix

Date	New Record	Previous Record
September 16th	A record high temperature of 92°F.	This tied the previous record of 92°F set back in 1993°F.

September 2012 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 2012 Observations:

	San Juan	Saint Thomas	Saint Croix
High	90.9°F(+1.7°F)	89.1°F(-0.9°F)	88.6°F(-0.4°F)
Low	78.9°F(+1.1°F)	79.0°F(+1.1°F)	75.5°F(-1.8°F)
Avg. T	84.9°F(+1.4°F)	84.0°F(0.0°F)	82.0°F(-1.1°F)
Pcpn.	2.13" (-3.64")	0.92" (-4.66")	3.74" (-1.12")

September 2012 extremes:

	San Juan	Saint Thomas	Saint Croix
High	93°F September 22nd	92°F September 24th,23rd and 17th	92°F September 16th
Low	76°F September 25th	76°F September 25th,13th and 12th	73°F September 1st

Monthly Summary

A generally fair and mainly dry weather pattern prevailed across Puerto Rico and US Virgin Islands with limited afternoon convection focused across western Puerto Rico each day. Brief periods of passing showers and thunderstorms were noted a few times, and were associated with the passage of weak easterly disturbances. However, rainfall accumulations associated with the aforementioned disturbances were marginal, and there is a lack of rainfall across portions of Eastern Puerto Rico as well as Saint Thomas. Overall, for the San Juan Metro Area, September 2012 can be described as a dry and hot month.

Rainfall Accumulations Year to Date (YTD)

Figure A – Graphical Display of precipitation for September 2012 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.

Figure C – Graphical display of departure from normal precipitation YTD.

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	66°F September 16th, 1972	65°F September 8th, 1982
69 °F September 6th, 1960	68°F September 11th, 1991	65°F September 25th, 1975
69°F September 29th, 1955	68°F September 8th, 1979	65°F September 17th, 1975

Wettest Septembers:

San Juan	Saint Thomas	Saint Croix
15.15" 1996	14.94" 1953	21.39" 1979
14.83" 1989	13.89" 2004	19.15" 1996
13.68" 1928	12.86" 2008	9.80" 1953

Driest Septembers:

San Juan	Saint Thomas	Saint Croix
1.49" 1940	0.92" 2012	1.07" 1981
1.73" 1987	1.08" 1986	1.64" 2001
1.78" 2006	1.42" 1987	1.96" 1986

Decadal September Observations for San Juan, Puerto Rico

	2010-2012	2000’s	1990’s	1980’s	1970’s	1960’s
High	89.1°F	89.2°F	89.3°F	89.9°F	88.4°F	87.8°F
Low	78.0°F	77.2°F	76.9°F	76.6°F	76.9°F	74.9°F
Avg. T	83.5°F	83.2°F	83.1°F	83.2°F	82.7°F	81.4°F
Pcpn.	5.87"	5.86’’	6.44’’	4.61’’	6.02’’	5.83’’

Looking ahead toward the month of October

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

	San Juan	Saint Thomas	Saint Croix
High	88.4°F	88.8°F	87.8°F
Low	76.9°F	76.8°F	76.4°F
Avg. T	82.6°F	82.8°F	82.1°F
Pcpn.	5.59’’	5.42’’	5.25’’

Moon/Sun/Tide Data for the Month of October 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

National Weather Service Weather Forecast Office