SAN FRANCISCO — The report cards are out and some U.S. states are better prepared for climate change threats than others. Eighteen states got an overall D or worse.

America’s Preparedness Report Card, released in November, rates U.S. states on factors such as extreme heat, summer droughts, wildfires and flooding. The letter grades are tabulated by comparing what precautionary steps a state has taken relative to the climate threats it is expected to face in the future. Getting a high ranking doesn’t mean states can slack off, though, climate scientist Rita Yu of Climate Central, which coproduced the report, explained December 15 at the American Geophysical Union’s fall meeting.

“An A doesn’t mean California is fully prepared for climate change and doesn’t need to do any more and can relax,” Yu said. “What it means is California is well ahead of other states … but there’s always room for improvement.”