Boston Harbor Islands State Park Rainfall ForecastUnited StatesMAPlymouth CountyBoston Harbor Islands State ParkToday 16 Apr5%Thu 17 AprNo RainFri 18 Apr20%Sat 19 Apr35%Sun 20 Apr15%Mon 21 Apr10%Tue 22 Apr35%Boston Harbor Islands State Park rainfall forecast issued today at 9:08 am. Next forecast at approx. 11:08 pm.1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast NOAA Rain Today Real-Time Boston RadarNational SatelliteNational SynopticGet WillyWeather+ to remove ads