You could ask the same question for a blizzard hitting New York or a tornado hitting Kansas. Only God can tell where these natural phenomenom hit. All you can do is gage yourself on the past track record. For instance, I live in Santo Domingo and in my livelihood have experienced David (1979), George (1998). So, they are not so frequent.
Historically the peak month for hurricanes in the Dominican Republic is September.
The south is the worst hit areas, but there are forecasts for hurricanes to move more northerly, so this means the north coast is not exempt from receiving a hurricane. In 2004, it was affected by Tropical Storm Jeane that went north.
See
http://dr1.com/weather/hurricanes.shtml for a historic breakdown of hurricanes in the DR.