Who can predict the weather? Certainly not me, nor can the forecasters on television. They can give you an idea on the range of the temperatures and the chances of precipitation but Mother Nature will do as she pleases. I live in New England and she really likes to play with us.
The weather in the Dominican Republic is pretty much the same for over 300 days of the year. You can expect your days to be partly sunny with a possibility of a brief shower thus making it extremely important to wear sunscreen and a hat. The temperatures will average between 80F and 90F degrees and your water temps will be between 79F and 83F degrees.
December through April are considered the cooler months when nighttime temps drop to around 66F degrees and the highs during the day reach 83F. May and June and October and November are usually considered to be the wettest months. You can expect short showers. These short showers last 5 or ten minutes and then the sun comes back out again. “They” say that the Dominican people have umbrellas but do not own raincoats.
Although hurricane season in the Caribbean in late June through to the end of November; it would be rare for hurricanes in June and July as the water temperatures are not warm enough to support the appropriate conditions and August and September are too hot.
Are you worried that your whole vacation will be rained out? If you are visiting the island for a week; you can expect four perfect days. Reality is that the Dominican Republic has very few rainy days, only short showers. Unless there is a tropical storm in the area; your vacation should not suffer due to weather.
I have visited the Dominican Republic about a dozen times so far and have always visited in October or November. We have experienced maybe 9 or 10 rainy days where we have not been on the beach or by the pool. Those are pretty good odds to me. I hope we continue to be lucky.
All in all, you shouldn’t let the weather in the Dominican Republic rule your decision to visit. The weather that you should concern yourself with is the chilly weather that you will be escaping and not what you will experience.