Analysis of a unique satellite precipitation dataset coupled with an extensive database of storm tracks are used to develop a parameter called the “millimeter-day (MD).” MD analysis in 4 mini-basins near the coastal southeastern United States reveals that September and October account for the largest number of extreme rainfall days (e.g. “wet millimeter-days” or MD > 0) during the 1998-2006 Atlantic hurricane season. Tropical cyclone (TC) days are more likely to produce wet millimeter days than non-TC days and category 3-5 hurricane days (e.g. major hurricanes) produce the largest magnitude wet millimeter-days. While major hurricanes produce the most extreme rainfall days, tropical depression/storm days contribute most significantly to cumulative rainfall (8-17%, basin-dependent) for the season due to frequency of occurrence. The influence of major hurricanes on rainfall may be most apparent in extreme daily events while weaker storms may be more critical for assessing trends in cumulative seasonal rainfall.