Gardeners know the frustration of a false spring. Coaxed outside by warm weather, some people plant their gardens in the spring only to see a sudden late frost strike at the plants with a killer freezer burn. Grumbling green thumbs, along with farmers and water supply managers, would benefit from more accurate predictions of the first and last frosts of the season.
Such timing is in flux, however. The frost-free season in North America is approximately 10 days longer now than it was a century ago. In a new study, published today in Nature Communications, researchers from the University of Utah and the U.S. Geological Survey parse the factors contributing to the timing of frost in the United States. Atmospheric circulation patterns, they found, were the dominant influence on frost timing, although the trend of globally warming temperatures played a part as well.
