Puerto Rico lies at the eastern end of the major island chain of the Greater Antilles. The other islands in the chain, Cuba, Jamaica, and Hispaniola (Haiti and the Dominican Republic) are larger and geographically more diverse. Puerto Rico's total area, including its neighboring island municipalities, is about 3,515 square miles (9,104 square kilometers). Its two island municipalities, Vieques and Culebra lie east of Puerto Rico proper. In the west are three smaller island dependencies; Mona, Monito, and Desecheo. The relatively smooth coastline is fringed by many small islands and cays, especially in the south and east. The island is roughly rectangular in shape and stretches for 110 miles (180 kilometers) from east to west between Punta Jiguero and Punta Puerca, with a width from north to south averaging 35 miles (56 kilometers).
Deep oceanic waters fringe Puerto Rico. The Mona Passage, which separates the island from Hispaniola to the west, is about 75 miles (120 kilometers) wide and more than 3,300 feet (1,000 meters) deep. Off the northern coast is the 28,000 foot (8,500 meter) deep Puerto Rico Trench, and to the south the sea bottom descends to the 16,400 foot (5,000 meter) deep Venezuelan Basin of the Caribbean. Only to the east is there a broad continental shelf where the islands of Vieques and Culebra are structural continuations of the nearby Virgin Islands.
Puerto Rico is topographically rugged; its surface consists largely of hills, slopes, and mountains. The mountainous core is formed by the Cordillera Central and the Sierra de Luquillo, continuations of the Cordillera Central on neighboring Hispaniola. Both mountain ranges represent uplifted old surfaces strongly dissected by river erosion. Hill regions of equal irregularity and unevenness extend north and south of these mountains. Only 30 percent of the island can be classified as level or undulating, mostly in the form of an encircling narrow coastal plain.
The island is situated firmly within the zone of the trade winds, which blow from the east and northeast most of the year, and it has equitable temperature ranges differentiated only by altitude: tierra caliente (hot, tropical) on the plains and low hills and tierra templada (moderate, subtropical) in the mountains. Extreme temperatures are rare, the average minimum and maximum being 63° F (17° C) in February and 88° F (31° C) in August. Great variability in precipitation, however, is the norm. Easterly waves, las ondas alisias, move westward within the trade-wind zone and cause frequent intense rains that at times last two to three days without interruption. Hurricanes every so often strike Puerto Rico and every year some pass near enough to affect the island's climate particularly causing heavy precipitation during early fall, August to October. Cold fronts during the winter months occasionally bring relatively cold north winds, the "nortes", which can drop the island's north coast temperatures into the 60° F (16° C) range.
North of the mountainous interior it is wet with between 80 and 120 inches (200 and 300 centimeters) of rain annually. At the northeastern end of the island lies the El Yunque (The anvil) rain forest where the sounds of the coqui frog can be heard in all its splendor at night. In the south of the mountain backbone it is relatively dry with between 40 and 50 inches (100 and 125 centimeters). The high temperatures throughout the year result in high evaporation rates of surface moisture so that a section of Puerto Rico has semiarid conditions.
In terms of its cruising potential the north coast hasn't that much to offer the cruiser looking for good anchorages and tranquil beaches, yet if the cruiser takes the north shore route from the Dominican Republic or from the Turks & Caicos, a stopover in San Juan is worthwhile for the restaurants, casinos and other amenities a large and cosmopolitan city can offer. The West coast has some good areas south of the city of Mayaguez with Puerto Real and Boqueron good protected bays and a tranquil relaxing pace in the towns. In fact, there are many cruisers who have stayed for years in these areas. For me, however, the south coast of Puerto Rico is another world and it has great appeal. It is in the south coast that most of the good safe hurricane holes are found, and some of them hardly ever used. La Parguera is famous for its Phosphorescent Bay and its beautiful mangroves. Guanica is the first bay with true weather protection but not much else to offer. The next bay of consequence is Guayanilla, but since its the home of an oil refinery, you don't wan't to do much there. Ponce Bay has some anchorages but no real place to hole up in bad weather. The nice thing, however, is that you're only a short distance from Caja de Muerto (Coffin Island) which has the finest beach in the south coast of Puerto Rico but not good protection from anything except a southeast wind.
From here you go on to the best anchorage on the south coast, the Playa de Salinas. Regardless of what the name implies, there is no beach here, but a firm mud/sand bottom with about 10-12 ft sorrounded by mangrove. Very close by is the Bahia de Jobos area (Jobos Bay) with very good anchorages but no facilities. There is a private yacht club here but limited to 5 ft draft vessels. Inside this bay there is an area called Mar Negro (Black Sea) that is a very well protected and hardly used hurricane hole with numerous canals surrounded by mangrove. There is a man-made port in Pozuelo that offers little. The town of Arroyo has a series of docks at its dredged waterfront, but the breakwater allows buildup of sand inside the harbor making it useless, unless it has been recently dredged. A little further up the coast is where I used to have a beach house, el Bajo de Patillas (or Puerto Patillas as is named on the charts). There is good anchorage here as the area is well protected from everything but a southern blow, and then all the boats go to Jobos Bay to get protection.
As you continue to the southeast corner of Puerto Rico and turn north you get to Palmas del Mar, a man-made bay with an entrance that can be quite dangerous in bad weather but with a very well protected interior anchorage and marina. This is where the east coast begins and where most of the boating and cruising is done in Puerto Rico. The Puerto del Rey Marina is a world class affair with all the amenities and is only a short hop to the Virgin Islands. Going north you end up in the boating capital of Puerto Rico, the town of Fajardo. With several marinas, all kinds of repair facilities, availability of charter boats and haul-out for just about any size vessel this is a good stop-over before going to the beautiful islands of Culebra or Vieques, the Spanish Virgin Islands.
Vieques and Culebra are two jewels in every sense of the word, with pristine waters and white sand beaches. I won't say more now but select them on the menu for a more expanded visual cruise.