E.V. shivers through coldest January since ’79

By Mike Branom, Tribune

February 1, 2007

Congratulations, East Valley residents and winter visitors: We’ve just endured the coldest January in 28 years. According to the National Weather Service, Phoenix’s official thermometer recorded for the month an average temperature of 52.9 degrees — 3.1 degrees below normal.

Looking at all the Januaries since 1971, 2007’s ranks as the sixth coldest, and not since 1979 has a year’s opening 31 days been so chilly. “I don’t remember it being warm,” Tony Haffer, meteorologist in charge of the Weather Service’s Phoenix office, said when reminded that Jan. 9 experienced a high of 78. “It was obliterated by all the cold stuff.” When just considering this January’s average high temperature, the ranking is even more dramatic. That mark of 63.6 degrees is the fourth coldest since 1971. Haffer explained the low temperatures in the Valley are creeping upward, because of the urban heat island effect. The sprawl of concrete and asphalt means the heat created by sunlight can’t dissipate at night as fast as decades before. Responsible for the cold weather, Haffer said, was a high-pressure system over the Pacific Northwest. That system’s clockwise rotation pumped cold air from the north down to Arizona.