If Philadelphia has a run of abnormally hot weather this summer, it will be considered less unusual than it would have been a year ago. That’s because “normal” now has a new definition. A set of updated national climate averages due to be released this week shows that average summer temperatures in the city are nearly 2°F warmer than the benchmarks meteorologists have been citing for the past decade.
The updates come from the National Oceanic and Atmospheric Administration (NOAA), which will impliment its new 30-year “Climate Normals” on July 1. When weather forecasters use terms like “above normal” or “below normal,” they’re referring to average temperatures and precipitation figures compiled from daily, monthly and yearly readings at thousands of locations across the country during the previous three decades. The normals that are about to expire are based on conditions from 1971–2000; the new ones start in 1981 — and unlike their predecessors, they include the first decade of the 21st century, which was among the hottest on record for the country (and was the hottest on record globally). They also exclude the 1970s, which was a particularly chilly decade in many areas. As a result, the new normal temperatures for Philadelphia and the rest of the nation are higher than the previous set.[More]
So now you know how the average temperature is calculated. And every state in America is about to see the average temperature go up.
Winter temperatures showed more warming than the summer temperatures. Night temperature increased more than day time temperatures. Both bits of data that support human-caused climate change.
Just another indicator of how much warmer things are getting. And that we have a role.