Hispaniola is a tropical island.  Average temperature throughout the year is 77 F (25 C); however, the island has the greatest mini-climate diversity in the Caribbean. In the high mountain regions, such as those around Constanza and Pico Duarte, temperatures have been registered as low as 0!  And rainfall levels vary not only from season to season, but from one valley or peak to another.  Some areas receive 70-100 inches of rainfall annually (1750-2500 mm), while others receive only 25-35.  Much of the difference depends upon the flow of air from the moisture-laden Trade Winds and upon a region's location with respect to land formations that block the Trade Winds.

Overall temperatures in the Dominican Republic are somewhat cooler from December to February, and hottest in June through August. I n general, however, the temperature differential is greater from night to day than it is from season to season! Temperatures change more rapidly in the tropics with altitude (10 for every 1000 meters of elevation) than they do from season to season. 

Afternoon showers are common year round--be sure to bring along an umbrella--but the heaviest rainy season is normally between May and August (when the sun is hottest), with the least rainfall in November and December.  Hurricane season officially runs from June 1 to the end of November, though August through mid-October are the months with the most potential of danger from these tropical storms, and six out of every ten hurricanes that have hit the Dominican Republic since 1871 have done so in September.

  Climate-related travel tips: 

       Umbrellas have two well-deserved names here. They are called both paraguas and sombrillas. The first means "stop the (rain)water," and the second "shade maker."  It's a good idea to bring along a collapsible umbrella and keep it handy at all times for both purposes. 

       The tropical sun is hot and fierce. Do not underestimate it. Bring along lots of waterproof sun protection lotion and use it. And drink lots and lots of water so that you do not become dehydrated.