Dr. Legates has been published more than 125 times in refereed journals, conference proceedings, and monograph series and has made more than 250 professional presentations. His research has appeared in such journals as the International Journal of Climatology, The Professional Geographer, Journal of Geophysical Research, Journal of Environmental Hydrology, Journal of Climate, Climatic Change, Bulletin of the American Meteorological Society, Water Resources Bulletin, Geographical Review, Global and Planetary Change, Journal of Hydrology, Theoretical and Applied Climatology, The American Cartographer, and Journal of Geophysical Research. He is a contributor to the Encyclopedia of Climate and Weather and Yearbook of Science and Technology.

He has argued for the necessity of technological progress in precipitation measurement used for validating climate change scenarios and for validation of existing data used for that purpose. He codeveloped methods to correct bias in gauge-measured precipitation data for wind and temperature effects, with direct applicability in climate change, hydrology, and environmental impact studies. Legates also developed a calibration method that validates NEXRAD radar precipitation data with gauge measurements to improve the accuracy of precipitation estimates.

Dr. Legates has earned certified consulting meteorologist status from the American Meteorological Society and in 1999 was awarded the Boeing Autometric Award for submitting the best paper in image analysis and interpretation. At the 14th International Conference on Climate Change in 2021, he received the Frederick Seitz Memorial Award, and at the 10th International Conference on Climate Change in 2015, he was presented with the Courage in Defense of Science Award.