Princeton University researchers say extremely sunny or cloudy days are more common than in the early 1980s, and swings from thunderstorms to dry days rose considerably since the late 1990s.
These swings could have consequences for industries such as agriculture and solar-energy production, which are vulnerable to inconsistent and extreme weather, the researchers said in a release issued by the Ivy League school in New Jersey Tuesday.
Existing climate-change models have historically been based on monthly averages, an approach that hides variability, David Medvigy, an assistant professor in the Department of Geosciences, said.
"Monthly averages reflect a misty world that is a little rainy and cloudy every day. That is very different from the weather of our actual world, where some days are very sunny and dry," Medvigy said.
"Nobody has looked for these daily changes on a global scale. We usually think of climate change as an increase in mean global temperature and potentially more extreme conditions -- there's practically no discussion of day-to-day variability."
Analysis of erratic daily conditions such as frequent thunderstorms may be crucial to understanding factors shaping the climate and affecting the atmosphere, the researchers said.