According to estimates from the National Center for Atmospheric Research, the baseline cost of extreme weather (which has always been with us, but which is steadily getting worse due to climate change) in the United States is $485 billion a year — 3.4 percent of the country's GDP.
This is a complicated number — it includes not only immediate costs from weather destruction, but also lost crops, power outages, resource usage, retail demand changes, and other indirect effects. Plus, it takes into account the fact that severe weather can be a boon for some industries (snow for ski resorts, for instance, or droughts for outdoor construction). Add it all up, and you get a chunk of change equivalent to a third of the U.S. budget deficit.
Just for perspective, House Republicans put a stop to the composting program in Congressional cafeterias, citing budget reasons, because it cost $475,000. That's 1/1000th as much as severe weather.