Because of Trinidad’s southerly location, temperatures are equable year-round. Its average daily temperature is 27°C (80°F). Average humidity hovers around 75%.
The only real seasons in Trinidad and Tobago are the rainy season (June to November) and the dry season (December to May). The high season is January to March, with a noticeable peak in February when Carnival draws hordes of visitors and the cost of hotel rooms skyrockets. Booking ahead is essential at this time.
Accommodations are cheaper and crowds almost nonexistent in the shoulder seasons – October to December and April to June – though you should do a little dance to ingratiate the rain lords.
Sitting outside the hurricane belt, the islands generally don’t experience the severe storms like northerly islands.
(source: http://www.lonelyplanet.com/trinidad-and-tobago/weather#ixzz1s0lqGY51)