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Bakersfield's new normal temperatures are hotter than the old normals

On Tuesday, Bakersfield's warming climate officially pushed the new normal even higher.

Each decade, scientists at the National Oceanic and Atmospheric Administration calculate the "normal" temperatures we can expect to see each day, each month and each year in Bakersfield and myriad other locations across the lower 48 states.

The NOAA calls them climate normals, but these normals, averaged over three decades, don't stay put. They change if and when the climate changes.

And it did. The decade that ended last year was the hottest decade recorded since 1880, according to NOAA's National Centers for Environmental Information.  

"Each new decade the normals are recalculated," said Colin McKellar, a meteorologist and back-up climate specialist at the National Weather Service in Hanford.

For the past decade, climatologists have used the 30-year period from 1981 to 2010 to calculate "normal" temperatures. But on Tuesday, the NOAA update shifted that 30-year block to the 1991-2020 period.

Naturally, the changes to daily averages are less dramatic than monthly or yearly averages.

"You'll see more difference in the monthly averages," McKellar said.

For example, before Tuesday's update, if your favorite TV meteorologist reported the average — or "normal" — high temperature for the month of May, he or she probably would have said 83.5 degrees, because that was the normal maximum temp for May.

But rising average highs in Bakersfield over the past decade have pushed monthly normal highs, well, even higher. According to the updated normals, the new normal for daily high temperatures in May is 84.1 degrees.

For residents of the southern San Joaquin Valley, these rising normals shouldn't come as a shock as five of the warmest years in Bakersfield’s recorded history have occurred within just the past seven years.

"Temperatures are going up in the summer," McKellar said. "Annual precipitation is coming down."

All true, but normal temperatures as reflected in the new, 30-year averages are up not just in summer, but for every month of the year.

That may mean nicer, sunnier days in the winter, and even lower heating bills, but balmy winters may have a significant impact on some of Kern's most valuable crops, some of which require an extended period of cold during the winter to generate healthy yields at harvest time.

Now that the NOAA update has shifted the baseline for "normal" to higher temperatures, does it mean weather forecasters in Kern County will not report as many "above normal" days? Will our weather become "milder" overnight because our definition for "normal" has changed?

"We don't want to keep an old set of normals," McKellar said. "We want these normals to reflect more current information."

It makes sense. But residents of Bakersfield, or Fresno, or Phoenix or dozens of other cities that are experiencing more than a half-century of rising temperatures should understand.

It's not normal.

Reporter Steven Mayer can be reached at 661-395-7353. Follow him on Facebook and on Twitter: @semayerTBC.