Owing to its diverse mountainous topography the country's climate shows considerable variation for its size, and has the most diverse climate zones of all the Caribbean islands. Conditions are ameliorated in many areas by elevation and by the northeast trade winds, which blow steadily from the Atlantic all year long. The annual mean temperature is 25 °C (77 °F); regional mean temperatures range from 18 °C (64.4 °F) in the heart of the Cordillera Central (Constanza) to as high as 27 °C (80.6 °F) in arid regions.