2011 Climate Summary

Areas of Excessive Rainfall and Dangerous Heat

Heavy to severe thunderstorms may bring areas of excessive rainfall and flooding over parts of the southern Plains through Friday. Hot to dangerously hot temperatures are forecast again across portions of the Pacific Northwest and southern Great Basin Tuesday. Read More >

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

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