Both Trinidad and Tobago lie deep in the tropics but are cooled by the marine environment and the prevailing northeast trade winds. Because of its constant exposure to trade winds, Tobago is cooler than Trinidad. Rainfall is moderate to heavy with an annual average of 82.7 inches but is subject to considerable regional and year-to-year variations. Days are warm, but evening temperatures are cooler. The seasonal variation does not exceed 5°F. The mean year-round temperature for the country at 8 a.m. is about 77°F; at 2 p.m. it is about 86°F. Humidity averages about 86% at 8 a.m. and about 65% at 2 p.m.
A dry season, more clearly defined than in most West Indian islands, lasts from January through mid-May; a short interruption of the rainy season also usually occurs in September. In most of the country no month is entirely dry, but during the rainy season the monthly precipitation is three to four times greater than in the dry season.
Although the country lies slightly south of the hurricane track, violent local storms sometimes occur. In 1962, Hurricane Flora devastated Tobago, and tropical storm Alma crossed Trinidad in 1974. Both events are considered highly unusual.