The day-to-day weather may be the source of lots of small talk, but that comes at a big price.

A study released by the National Center for Atmospheric Research in Boulder, Colo., says the annual impact of routine weather in the United States can total $485 billion.

Economist and lead study author Jeff Lazo says "it's clear that our economy isn't weatherproof." He adds in a statement that even routine changes in the weather can have a substantial impact on the economy.

"Weather directly and indirectly affects production and consumption decision-making in every economic sector of the United States," the researchers reported. "From very local short term decisions about whether or not to pour concrete on a construction project to broader decisions of when to plant or harvest a field, to the costs of rerouting an airplane around severe weather, to peak demand electricity generation in response to extreme heat, to early season snow for a bumper ski season in Colorado, drought in the Midwest, or wind-fueled wildfires in California, weather can have positive or negative effects on economic activity."

The researchers studied 70 years of weather records, through 2008, from across the contiguous United States.

The study, being published in the Bulletin of the American Meteorological Society, focused on variations in temperature, total precipitation and deviation from average precipitation.

It did not take into account the additional costs of extreme weather, such as this year's tornado outbreaks, or the possible impacts of climate change, which is expected to lead to more flooding, heat waves, and other costly weather events.

Every state is sensitive to the weather in one way or another, the researchers concluded. In terms of gross state economic output, New York was the most sensitive and Tennessee the least, they reported.

Mining and agriculture are particularly sensitive to weather, the researchers reported. Other sensitive sectors include manufacturing, finance, insurance and utilities.