October 2012 Climate Report

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

October 2012 Highlights

New Records for October 2012

Date	New Record	Previous Record
October 28th	A record high temperature of 94°F.	This broke the previous record of 92°F set back in 1992 and 1971.
October 2012	October 2012 ended as the fourth warmest October on record with an average temperature of 83.9°F.	October 2009 ended as the warmest October on record with an average temperature of 84.4°F.

Saint Thomas

Date	New Record	Previous Record
October 21st	A record rainfall of 1.32".	This broke the previous record of 1.13" set back in 1998.
October 2012	October 2012 ended as the ninth warmest October on record with an average temperature of 83.3°F.	October 1993 ended as the warmest October on record with an average temperature of 85.5°F.

Saint Croix

Date	New Record	Previous Record
October 2012	October 2012 ended as the seventh warmest October on record with an average temperature of 82.7°F.	October 1972 ended as the warmest October on record with an average temperature of 84.3°F.

October 2012 Statistics

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’’

October 2012 Observations:

	San Juan	Saint Thomas	Saint Croix
High	89.9°F(+1.5°F)	87.9°F(-0.9°F)	88.3°F(+0.5°F)
Low	77.9°F(+1.0°F)	78.8°F(+2.0°F)	77.1°F(+0.7°F)
Avg. T	83.9°F(+1.3°F)	83.3°F(+0.5°F)	82.7°F(+0.6°F)
Pcpn.	4.67" (-0.92")	4.62" (-0.80")	2.64" (-2.61")

October 2012 extremes:

	San Juan	Saint Thomas	Saint Croix
High	94°F October 28th and 27th	92°F October 2nd	90°F October 31st
Low	74°F October 12th	75°F October 6th	73°F October 6th

Monthly Summary

Afternoon convection dominated the first half of October as a result of daytime heating and sea breeze convergence. The steering flow focused the afternoon shower activity along the western interior and western portion of Puerto Rico. By the end of the month, a broad area of low pressure across the western Caribbean became Hurricane Sandy, and affected Cuba and Hispaniola as it moved northward. Hurricane Sandy created an unusual wind field across the forecast area and brought deep tropical moisture from the southwest, as well as above normal temperatures along the north coast of Puerto Rico. Showers and thunderstorms associated with the outer bands were strong enough to produce moderate to major flooding across the Guayanilla and Caguas area between October 25th and October 27th.

Rainfall Accumulations Year to Date (YTD)

Figure A – Graphical Display of precipitation for October 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.

October Historical Statistics

Highest October Temperatures on record:

San Juan	Saint Thomas	Saint Croix
98°F October 9th, 1981	97°F October 14th, 1994	98°F October 1st, 1972
97°F October 13th, 1987	97°F October 13th, 1994	97°F October 11th, 1995
97°F October 12th,1987	97°F October 15th, 1993	95°F October 4th, 1972

Lowest October Temperatures on record:

San Juan	Saint Thomas	Saint Croix
67°F October 20th, 1959	66°F October 29th, 2007	65°F October 23rd, 1983
68°F October 30th, 2001	66°F October 28th, 2007	65°F October 22nd, 1983
68°F October 26th,1961	66°F October 27th, 2007	65°F October 31st, 1975

Wettest Octobers:

San Juan	Saint Thomas	Saint Croix
15.06" 1970	16.20" 2010	16.20" 1977
12.15" 1927	12.49" 2005	12.95" 1990
11.94" 2005	12.45" 1974	11.79" 1954

Driest Octobers:

San Juan	Saint Thomas	Saint Croix
1.17" 1979	1.95" 2011	1.05" 1964
1.61" 1915	2.00" 1988	1.10" 1990
1.63" 1963	2.21" 1979	11.79" 1954

Decadal October Observations for San Juan, Puerto Rico

	2010-2012	2000’s	1990’s	1980’s	1970’s	1960’s
High	88.6°F	88.2°F	88.6°F	89.2°F	88.3°F	87.5°F
Low	76.9°F	76.4°F	76.1°F	75.5°F	76.4°F	74.2°F
Avg. T	82.8°F	82.3°F	82.4°F	82.4°F	82.4°F	80.8°F
Pcpn.	6.01"	6.20’’	4.44’’	5.58’’	6.29’’	4.85’’

Looking ahead toward the month of November

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

	San Juan	Saint Thomas	Saint Croix
High	85.9°F	87.0°F	86.3°F
Low	75.2°F	75.2°F	75.0°F
Avg. T	80.6°F	81.1°F	80.7°F
Pcpn.	6.35’’	5.23’’	5.46’’

Moon/Sun/Tide Data for the month of November 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.

National Weather Service Weather Forecast Office