Upper Crystal Springs Reservoir Rainfall ForecastUnited StatesCASan Mateo CountyUpper Crystal Springs ReservoirToday 19 AprNo RainSun 20 AprNo RainMon 21 AprNo RainTue 22 AprNo RainWed 23 AprNo RainThu 24 AprNo RainFri 25 Apr15%Upper Crystal Springs Reservoir rainfall forecast issued today at 1:04 am. Next forecast at approx. 3:04 pm.1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast NOAA Rain Today Real-Time San Francisco RadarNational SatelliteNational SynopticGet WillyWeather+ to remove ads