The risks of extreme weather events are typically being estimated, by federal agencies and others, with historical frequency data assumed to reflect future probabilities. These estimates may not yet have adequately factored in the effects of past and future climate change, despite strong evidence of a changing climate. They have relied on historical data stretching back as far as fifty or a hundred years that may be increasingly unrepresentative of future conditions. Government and private organizations that use these risk assessments in designing programs and projects with long expected lifetimes may therefore be investing too little to make existing and newly constructed infrastructure resistant to the effects of changing climate. New investments designed to these historical risk standards may suffer excess damages and poor returns. This paper illustrates the issue with an economic analysis of the risks of relatively intense hurricanes striking the New York City region.