According this this Washongton Post article, 243 million Americans affected by weather disasters since 2007

Drought, record heat and Hurricane Sandy were among the major weather-related disasters that affected the United States in 2012. But just how many Americans felt the impact of these events? A newly released report from the Environment America Research and Policy Center says 243 million people – nearly 80 percent of the U.S. population – live in counties that experienced at least one weather-related disaster since 2007.

Related articles

• Nearly 80 Percent Of Americans Hit By Extreme Weather Disaster Since 2007, Report Finds (thinkprogress.org)
• Interactive Map Reveals Extreme Weather Disasters Impact 80 Percent of Americans (Map) (scienceworldreport.com)
• Report: 243 million Americans affected by weather disasters since 2007 (washingtonpost.com)