Portsmouth Harbour - HMNB Portsmouth Rainfall ForecastUnited KingdomSEHampshirePortsmouth Harbour - HMNB PortsmouthToday 24 Aug5%Tue 25 Aug40%Wed 26 Aug65%Thu 27 Aug65%Fri 28 Aug40%Sat 29 Aug55%Sun 30 Aug55%1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast Met Office Rain Today Real-Time Portsmouth Harbour - HMNB Portsmouth rainfall forecast issued today at 7:08 am. Next forecast at approx. 9:08 pm. Rainfall Rainfall AccumulationDean Hill (Wiltshire) RadarGet WillyWeather+ to remove ads