Phoenix sets record for most 100-degree days
The unrelenting and unprecedented heat that scorched Phoenix all summer, setting records, has carried over into the fall. Now it has set another blistering milestone: the most 100-degree days ever observed in a calendar year.
On Wednesday, the temperature in Phoenix climbed to at least 100 degrees for the 144th time in 2020, surpassing 143 in 1989 for the most such instances on record. The1989 record could fall as soon as Wednesday, when a high temperature of 101 degrees is forecast.
Half of the days (144 out of 288) of the year so far, equivalent to 20.4 weeks, have hit 100 degrees. Several more such days are likely.
In recent decades, Phoenix has averaged about 110 days hitting 100 degrees or more per year. That’s up from about 75 in the mid-1920s.
The overall 2020 heat records in Phoenix are too many to list. But among the more notable are new highs for the number of days at or above 110 (53) and 115 (14) degrees. Not to mention, Phoenix never dropped below 90 degrees for a record 28-night stretch during the summer.
“2020 has pretty much broken every other heat record,” wrote Amber Sullins, chief meteorologist at Phoenix’s Abctelevision affiliate, in an email.
Often, in the late summer and early fall, Pacific moisture enters the desert southwest, lowering temperatures. But in 2020, the Northamericanmonsoon, which ordinarily draws this moisture inland, was unusually weak. Widespread drought resulted.
Sullins wrote: “100 percent of Arizona is in drought right now.”
Heading deeper into October, the odds of 100-degree days normally shrink quickly. But this year the decline may be more gradual.
“The outlook over the next couple of weeks is warmer and drier than normal,” Sullins wrote. She noted that this fall’s La Niña event, characterized by cooler than normal ocean waters in the tropical Pacific, tends to favor drier-than-usual conditions into the winter.
Temperatures are forecast to remain near 100 degrees through at least Friday. Long-range forecasts suggest that above-average temperatures are likely for much of the rest of the month, and perhaps beyond.