Harwell Rainfall ForecastUnited KingdomSEOxfordshireHarwellToday 18 Nov50%Wed 19 Nov50%Thu 20 NovNo RainFri 21 Nov20%Sat 22 Nov45%Sun 23 Nov15%Harwell rainfall forecast issued today at 12:36 am. Next forecast at approx. 2:36 pm.1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast Met Office Rain Today Real-Time Chenies (Hertfordshire) RadarNational SatelliteNational SynopticGet WillyWeather+ to remove ads