Legates received a B.A. in Mathematics and Geography (double major) in 1982, a M.S. in Geography-Climatology in 1985, and a Ph.D. in Climatology in 1988, all from the University of Delaware.  His expertise lies in hydroclimatology/surface water hydrology, precipitation and climate change, spatial analysis and spatial statistics, and statistical/numerical methods.  Legates’ dissertation was entitled “A Climatology of Global Precipitation” and focused on obtaining a better picture of global precipitation by incorporating a high-resolution precipitation gage database that was adjusted for changes in instrumentation and biases associated with the precipitation gage measurement process.  His climatology of precipitation continues to be widely used as it is still the only global climatology available that addresses the gage measurement bias problem.

Upon receiving his Ph.D., Legates became an Assistant Professor in the College of Geosciences at the University of Oklahoma.  He was granted tenure and promoted to Associate Professor in 1994.  He became the Chief Research Scientist for the Center for Computational Geosciences at the University of Oklahoma in 1995.  In 1998, Legates moved to the Louisiana State University and became an Associate Professor in the Department of Geography and Anthropology as well as a research scientist with the Southern Regional Climate Center.  Legates then returned to the University of Delaware in 1999 as an Associate Professor and was promoted to Full Professor in 2010.  While at Delaware, Legates has served as the Delaware State Climatologist (2005-2011), Director of the Center for Climatic Research (2001-2007), founder and co-Director of the Delaware Environmental Observing System (2003-2011), and Coordinator of the Delaware Geographical Alliance, now known as the Delaware Center for Geographic Education (2005-present).

Legates has been invited to speak to the US Senate Committee on the Environment and Public Works on three separate occasions as well as both Pennsylvania House and Senate Committee meetings focusing on climate change.  He also participated in the historic joint USA-USSR protocol for the exchange of climate information in 1990, won the 2002 Boeing Autometric Award for the Best Paper in Image Analysis and Interpretation by the American Society of Photogrammetry and Remote Sensing, won First Place in the International Statistical Institute (ISI) and ESRI Paper Competition in Kuala Lumpur, Malaysia, and was awarded the Courage in Defense of Science Award in 2015.  He has received over $7M USD in grants over his career and has published more than 80 refereed articles.  He has made more than 250 professional presentations.