Previous research has shown that the northeastern United States experienced a significant increase in precipitation during the twentieth century, especially during the autumn. This shift toward wetter conditions can be explained by examining trends in daily precipitation characteristics. Early season precipitation changes in the western portion of the study area were associated with increases in the frequency of precipitation-days. Later in the season a coincident increase in precipitation-day intensity enhanced these trends. Tropical storms had little influence on autumn precipitation increases. The study suggests that, instead, changes in regional atmospheric circulation may be responsible for changing precipitation characteristics.