Patapsco River - Fort McHenry Marsh UV IndexUnited StatesMDBaltimore CityPatapsco River - Fort McHenry Marsh1-Day3-Day Graph Plots Open in Graphs UV Forecast NOAAPatapsco River - Fort McHenry Marsh UV forecast issued today at 3:18 pm. Next forecast at approx. 3:18 pm.Get WillyWeather+ to remove ads