WeatherSigma uses publicly available model data from the NOAA Operational Model Archive Distribution System (NOMADS), the European Center for Medium-Range Weather Forecasts, the Meteorological Service of Canada (etc. etc.). WeatherSigma uses publicly available observational data from the National Climatic Data Center, the National Weather Service, the Federal Aviation Administration, NOAA's U.S. Climate Reference Network, the National Interagency Fire Center, the Citizen Weather Observer Program (CWOP), the Natural Resources Conservation Service, the National Data Buoy Center, Environment Canada, and various transportation networks across the United States.