Climate Notes January/February 2008:

January marks the climatological beginning to the dry season here in Puerto Rico. On average, the Luis Muñoz International Airport receives only 3.24 inches of rain during the month of January*, making January the third driest month on the island, with only the months of February and March receiving less rainfall. January is also the coolest month on average here in Puerto Rico, with an average daily temperature of 76.8 ºF*, 0.2 ºF cooler than February, the second coolest month of the year.

Islandwide, Puerto Rico received, on average, approximately 0.11” more rainfall than normal, or 103% of the normal value, during the month of January. While above average precipitation for the month was recorded on the island, the first, third and fifth weeks of the month actually reported below normal rainfall, while the second and fourth weeks of the month were unusually wet (see attached graphic). The wettest portions of the island were the north coast and northern slopes of Puerto Rico, where approximately 150% of the normal rainfall was recorded, with the remainder of the island receiving between 70% and 90% of their normal precipitation. The highest maximum temperature was 90 ºF, reported in Lajas on the 5th of January, while the coldest temperature of the month was 43 ºF, reported in Aibonito on the 30th of January.

At the Luis Muñoz International Airport in San Juan, the average monthly temperature was 76.2 ºF, which was -0.6 ºF lower than normal*, with a maximum temperature of 84 ºF, reported on the 28th of the month, and a minimum temperature of 68 ºF, reported on the 27th. A total of 6.96 inches of rainfall was reported at the Luis Muñoz International Airport, which was 3.72 inches above normal and just shy of the record of 7.60” recorded in January 1977. The driest January on record was January 1978, when only 0.61” of rainfall was recorded in San Juan.

Looking ahead, February marks the second driest month at the Luis Muñoz International Airport in San Juan, with only 2.21 inches of rainfall received on average*. The average high temperature at the Luis Muñoz International Airport in San Juan for February is 77.0 ºF*, 0.2 ºF warmer than January. Presently, La Niña conditions are expected to continue through at least the spring, and a detailed summary of these current ENSO conditions and forecasts can be found at:

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf

* All climate averages for San Juan taken from 52 continuous year period of 1956-2007 *