How the new climate normal will change our weather reports
2 min read
The National Oceanic and Atmospheric Administration is about to add more recent data to its definition of 'normal' temperatures, which means additional hot days won't sound so warm by comparison.
It's a standard refrain in local weather reports, especially as climate change makes temperatures climb higher: How much hotter than normal is it? In Phoenix, where the city was hotter than 100 degrees for more than a third of the days in 2020, it was sometimes 10 degrees hotter than "normal." In San Francisco, where it's typically so cool in the summer that few people own air conditioners, a 99-degree day last August was around 20 degrees hotter than "normal." Parts of Alaska—where warming is happening fastest—have been 50 degrees hotter than "normal" in recent years.

"Normal," in this case, is based on three decades of historical data, from 1981 through 2010. But the data are periodically updated, and the National Oceanic and Atmospheric Administration's National Centers for Environmental Information will soon release new "climate normals" from the '90s through the 2010s. Because the 2010s were the hottest decade in recorded history, it…
Adele Peters
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