Bermuda Geography

What is the terrain and geography like in Bermuda?

Overview

Bermuda is an archipelago of seven main islands and some 150 other islands and islets. The main islands, joined by bridges or causeways, stretch from northeast to southwest in a long, narrow formation that hooks northward at the western end. On the map, the shape is much like that of a fishhook. The main islands are in close proximity and, since being joined, the Bermuda Islands (or Somers Isles, their other name) are generally called the island of Bermuda.

Bermuda’s total land area is about 20 square miles — some 22 miles in length and an average of less than a mile in width — making the country smaller than the city of Manhattan. During World War II, the U.S. military created 1.25 square miles of the present land mass by uniting and enlarging some of the islands with material dredged from the sea bottom, now the site of the Bermuda International Airport.

The archipelago is the summit of a submerged volcanic mountain range, 14,000–15,000 feet high, which has been extinct since before the first ice age. Between the volcanic foundation and the inches-thin layer of soil capping it lies a 200-foot thick layer of limestone formed by deposits of mollusks, coral polyps, and other sea creatures. The coral content in the limestone substructure justifies Bermuda’s classification as a “coral island,” though it is more fully described as a mixed superstructure of Aeolian petrified sand hills and limestone upon an eroded volcanic base. The surrounding reefs are true coral growths, making Bermuda the most northerly point on the globe where reef-building coral exists.

Bermuda lies at latitude 32’18” north and longitude 65’46” west. Geographically, it is remote and does not lie within or near the West Indies or the Caribbean, with which it is often erroneously identified.

The terrain is hilly, with the highest — Gibb’s Hill — 260 feet above sea level. A fertile valley extends along the length of the main island. Wind-carved cliffs cascade into the sea along the rocky northern shore. Similar rock formations form a dramatic backdrop for the long beaches and small coves along the south shore. The enclosing reef, a few yards offshore on the south coast and up to several miles offshore on the north, emerges from the sea each day at low tide, framing the islands and completing the topographical picture.

Except for a few small ponds, there are no rivers, streams, lakes, or other surface freshwater formations. For most of its history, Bermuda was thought to have no groundwater, but freshwater lens formations lying above underground saltwater were discovered in the 1920s and 30s. These have subsequently been exploited to supplement the island’s main source of drinking water, which is rainwater collected on roofs and paved catchments.

Geography - note

Consists of about 138 coral islands and islets with ample rainfall, but no rivers or freshwater lakes; some land was leased by the US Government from 1941 to 1995

Climate

Though far north from tropical latitudes, Bermuda has a mild, humid, frost-free climate. The annual mean temperature is 70.2°F. Highs in summer rarely top 90°F, and lows in winter rarely drop under the 50s. The lowest temperature ever officially recorded was 44°F. The Gulf Stream, running west and north of the island, is the main reason for the good climate. The average annual rainfall is 57.6 inches, spread evenly throughout the year. The year-round high humidity, averaging more than 75%, makes some days uncomfortably sticky in summer and damp and cold in winter.

January through March tends to be overcast and squally, although when the sun shines it can be like a breezy spring day. April and May are very pleasant. June through August are very hot and very humid. The heat factor (temperature plus humidity) during the hottest summer months can exceed 110°F degrees Fahrenheit. September is the stormy season, although hurricane season officially extends from June through November. Barring hurricanes, October through December are calm, mild, and usually sunny, and are considered by many to be the most pleasant part of the year.

The climate, well-distributed rainfall, and heavy dew promote the luxuriant growth of vegetation of every description, despite the dearth of soil. Palms, Australian and Norfolk Island pines, mangroves, poincianas, casuarinas, ficus trees, citrus, and some tropical fruit trees grow well in Bermuda. Prolific oleander and hibiscus brighten gardens and lanes everywhere. Sadly, the famous Bermuda cedar trees that for centuries dominated the landscape and were the islands' pride, were nearly all destroyed by blight in the 1940s. The few remaining native cedars are protected, and some reforestation with blight-resistant stock is underway.