Dominica Geography, Climate & Nature

Dominica lies in the Windward Islands of the Lesser Antilles, between Guadeloupe some 48 kilometres to the north and Martinique about 40 to the south, with the Atlantic on its east coast and the Caribbean on its west; it is 750 square kilometres, 47 kilometres long and 29 wide, oblong and slightly smaller than New York City. It is the last island of the arc to have formed, by volcanic action about 26 million years ago, and lies on two opposing tectonic plates, which is why so small an island has mountains approaching 1,500 metres: Morne Diablotins, the highest and the largest volcano, at 1,447 metres in the north, and Morne Trois Pitons at 1,423 in the south, the centre of the national park. East-west spurs run down to a narrow coastal plain studded with sea cliffs and never more than two kilometres wide; the extreme south-west is the exposed rim of a collapsed submarine caldera, ending at Scotts Head where the two seas meet.

Volcanism is everywhere still: the Boiling Lake, the second-largest hot lake in the world, in a dormant caldera that last erupted in 1880; the Valley of Desolation's mud ponds and small geysers; sulphur springs at Soufrière and hot springs in the Roseau valley. Among the most rain-drenched lands on earth, the island's runoff makes cascading rivers and natural pools, 365 rivers by the local count, the Indian River the widest. The west coast has dry shrubland; the interior is multi-layered rainforest, largely unexploited.

Roseau, capital and main port, sits on the sheltered south-west coast with 14,725 people; the second town, on Prince Rupert Bay in the north-west, has about 4,200 people, the cruise jetty and the Portsmouth Ferry Dock; the Kalinago Territory covers 3,700 acres of the remote Atlantic coast. Douglas–Charles Airport is on the north-east coast near Marigot, an hour from either town; Canefield's short strip is five kilometres from the capital.

Dominica's climate is tropical, moderated by the north-east trade winds and heavy rainfall: a tropical rainforest climate over most of the island, bordering on tropical monsoon in places, with warm temperatures all year and slight ranges because of the sea. Average daytime temperatures run from 26 degrees in January to 32 in June. The rain falls hardest on the steep interior, which is among the most rain-drenched land on earth and keeps the 365 rivers running; the western coastal strip is drier, with patches of dry shrubland. The steep slopes alter temperature and wind from valley to valley, so the Roseau valley and the mountain lakes are cooler and wetter than the coast.

The same trade winds develop into hurricanes in the northern summer, and the island lies squarely in their path: the season runs from early June to the end of November, and the Canadian advisory notes that even small tropical storms can develop quickly into major hurricanes. David in August 1979 destroyed or damaged three-quarters of the island's homes; Erika in August 2015 killed 30; Maria made landfall as a Category 5 on the night of 18 September 2017 and practically eradicated the vegetation. Earthquakes are a risk and tremors frequent; the eastern Caribbean is an active seismic zone with a tsunami risk.

Best Destinations by Month has the practical reading.

Dominica is the youngest island of the Lesser Antilles and the least cleared, and its forests hold plants and animals thought extinct on the islands around it. Two hundred bird species have been recorded, two of them endemic: the Sisserou or imperial amazon, the national bird on the national flag, 48 centimetres long, critically endangered and down to an estimated 50 mature individuals in 2019, and the Jaco or red-necked parrot, for which the Morne Diablotin National Park was created in January 2000 out of the Northern Forest Reserve and the Syndicate Parrot Preserve, designated an Important Bird Area in 2007. Four snakes, two of them endemic -- the Dominican blind snake and the Dominican boa -- and eleven lizards, with the endemic Dominican anole and ground lizard, share the island with the Lesser Antillean iguana, for which Dominica is the last major stronghold.

Offshore, the Caribbean side is home to many cetaceans: a group of sperm whales lives here year-round, spinner, pantropical spotted and bottlenose dolphins are common, and killer whales, false killer whales and pygmy sperm whales are seen less often. The Soufrière Scotts Head Marine Reserve protects the bay where the Caribbean meets the Atlantic, and the Cabrits National Park, 1,313 acres since 1986, protects forest, coral reefs and wetlands at the northern end.

The protected system began with Morne Trois Pitons National Park in July 1975, the country's first, a World Heritage Site since 1997; Hurricane Maria in 2017 practically eradicated the island's vegetation, and the forest has been regrowing since. No fuller species inventory was consulted beyond the sources named in the data file.

The animals a visitor may see are the parrots on the Syndicate trail in the Morne Diablotin National Park -- the Sisserou rarely, the Jaco more often -- the anoles and ground lizards on every wall, the iguana in the dry west, the boa in the forest, and from a boat off the leeward coast the resident sperm whales and the dolphins that travel with them. The Indian River's boat ride is the easy wildlife morning: the widest river on the island, rowed between the mangrove roots where scenes of Pirates of the Caribbean were filmed. The Boiling Lake trail is not a wildlife walk but a geology one, through the Valley of Desolation's sulphur and steam.

The practical zoology is the advisories': mosquitoes carry dengue, chikungunya and Zika, so cover up and use repellent; and the sea has rip currents and no lifeguards on most beaches.