2011 Climate Summary

Precipitation

2011 ranks as the second wettest year in nearly 113 years of record keeping in the San Juan Metro Area. An impressive rainfall total of 88.15 inches was reported at TJSJ, which is 31.80 inches above normal. This total was 1.35 less than 2010, the wettest year on record. According to Cooperative Weather Observer data, 2011 was a wet year across the entire forecast area, with 126% of the normal precipitation falling across all of Puerto Rico and 121% of the normal precipitation falling across the U.S. Virgin Islands. Not surprisingly, 2011 ranks as the ninth wettest year on record at TIST as well as TISX with a rainfall total of 46.14 and 47.72 inches respectively. Overall, 2011 produced 189 days of measurable rain at TJSJ, which means 52% of days where 0.01 inch or more accumulated. Meanwhile, 147 and 144 days of measurable rain were reported at TIST and TISX, resulting in 40 and 39% of the days where 0.01 inch or more accumulated.

Statistically, 2011 began with a rainfall deficit across the local islands with just 85% of the normal precipitation falling across all of Puerto Rico. The scenario changed around May when the wet season started. From May through September, a rainfall surplus of about 36 inches was reported at the San Juan Metro Area with 141% of the normal precipitation falling across all Puerto Rico. In fact, summer 2011 is the wettest summer on record at TJSJ with a rainfall total of 43.24 inches between June and August. One of the factors for the rainfall surplus across the local islands was a series of tropical systems including Tropical Storm Emily and Hurricane Irene. Remarkably, August 2011 ended as the wettest August on record as well as the wettest month ever across the San Juan Area with a rainfall total of 18.56 inches. 2011 also left several impressive records across the U.S. Virgin Islands including the driest January, second wettest June and the third wettest July on record at TISX as well as the wettest August and the driest October on record at TIST.

	San Juan	Saint Thomas	Saint Croix
1st	89.50" 2010	67.59" 1960	78.25" 1979
2nd	88.15" 2011	61.38" 2010	56.13" 2003
3rd	87.55" 1931	55.29" 2005	54.87" 1960
4th	84.97" 1950	51.93" 2003	53.33" 1952
5th	84.93" 1927	50.34" 1974	53.23" 1996
6th	78.96" 1902	49.34" 1981	51.72" 1974
7th	77.61" 1899	76.92" 1954	50.10" 1987
8th	77.28" 2005	46.30" 1958	49.88" 2010
9th	76.60" 1952	46.14" 2011	47.72" 2011
10th	75.70" 1901	46.13" 1979	45.76" 1953

*latest occurrences

Rainfall Totals for Puerto Rico and U.S. Virgin Islands.

Sector

Rain

Normal

PON

X North Coast

74.47

61.74

121%

X South Coast

46.32

33.63

138%

X North Slopes

78.81

62.75

126%

X South Slopes

71.91

61.43

117%

X East Interior

106.65

79.50

134%

X West Interior

100.06

80.80

124%

Puerto Rico Average

79.70

63.31

126%

X U.S. Virgin Islands

48.21

39.78

121%

PON= Percent of Normal Precipitation

Temperatures

	San Juan	Saint Thomas	Saint Croix
Avg. Maximum	85.7°F	85.3°F	85.7°F
Avg. Minimum	74.5°F	75.6°F	74.0°F
Mean	80.1°F	80.5°F	79.8°F
Days Max >= 90°F	26	25	7

Climate Charts for Luis Muñoz Marin International Airport on San Juan (TJSJ), Cyril E. King Airport on Saint Thomas (TIST) and Christiansted Airport on Saint Croix (TISX).

Fig. 1. Luis Muñoz Marin International Airport

Fig. 2. Cyril E. King Airport on Saint Thomas

Fig. 3. Christiansted Airport on Saint Croix

Sector	Rain	Normal	PON

X North Coast	74.47	61.74	121%
X South Coast	46.32	33.63	138%
X North Slopes	78.81	62.75	126%
X South Slopes	71.91	61.43	117%
X East Interior	106.65	79.50	134%
X West Interior	100.06	80.80	124%

Puerto Rico Average	79.70	63.31	126%
X U.S. Virgin Islands	48.21	39.78	121%

National Weather Service Weather Forecast Office