We're all too familiar with heat in these parts - but now we must warm up to the idea that 2012 is likely to tie the mark for the hottest year on record in Tucson.

"It's going to be close, but I'm pretty sure we're going to tie the record" at year's end Monday, said J.J. Brost, a meteorologist with the National Weather Service.

"The record, set in 1989, is 71.4 degrees," Brost said. "That's the average temperature for the entire calendar year. If our forecasts for the rest of this year are even fairly close, we'll end up at 71.4 degrees for this year."

By way of comparison, the normal average annual temperature - for the period from 1981 to 2010 - was 69.4 degrees.


Brost said he used the forecasted temperatures for the rest of the year to project possible changes in 2012's average temperature by year's end.

Those calculations "gave us 71.4 degrees for the average temperature," he said. "To be cautious, I dropped all the forecasts down by 2 degrees, in case it's cooler than expected, and we still end up with 71.4 degrees. Even if we increase the temperatures by 2 degrees, we end up at 71.4."


Many factors played a role in making this year so warm in Tucson.

Among them, Brost said, was the weather phenomenon known as La Niña - defined as lower than normal sea-surface temperatures in the central and eastern tropical Pacific Ocean that impact global weather patterns.

"At the start of winter and into spring this year, we were influenced by La Niña that kept us dry and provided warmer conditions," Brost said.

"We haven't seen the low-pressure systems that cool us down moving into the area" as frequently as in some other years, he added. "The high pressure has seemed a little more prevalent this year."

Another possible factor: drought.

Tucson has received only 7.66 inches of rainfall this year - about 4 inches below normal.

"We have been experiencing a fairly pronounced drought, and the factors keeping us dry and warm are kind of related," Brost said.

did you know?

The hottest year on record in Phoenix was 1989, when the average temperature for the year was 76.9 degrees. That was the same year in which Tucson's record of 71.4 degrees was set.

Yes, it's cooler here.

Source: National Weather Service

2012 weather events

• Hottest days: 109 degrees (Aug. 12-13) (Records.).

• Coldest night: 29 degrees (March 3).

• Rainiest day: 1.06 inches (July 15) (Record.) .

• Second earliest 100-degree day on record: (April 22) (Historical average is May 26; earliest ever is April 19, set in 1989).

• Days of triple-digit temps: 73 (11th most in Tucson history).

• Days in a row (June 11-July2) at or above 100 degrees: 22 (16th longest stretch of triple-digit days).

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• It's dry: Official readings at Tucson International Airport are almost 4 inches below normal yearly precipitation.

• Jan. 1: Warmest New Year's Day on record: 80 degrees. (The first week of January 2012 was the warmest Jan. 1-7 on record with 60.6 degrees average temperature).

• Feb. 14: Less than a half-inch of snow accumulates in the Foothills, Oro Valley.

• March 31: Tucson hits 90 degrees for the first time in 2012 (Historical average is April 10).

• April: Tucson hits 90 degrees or higher 14 times in April, the most since 1989.

• May 9: Haboob moves through Tucson between 2-3 p.m.

• May 31: Smoke from New Mexico's Whitewater Baldy Complex Fire moves into Tucson.

• June 16: First measurable monsoon rainfall (0.29 of an inch - record) at the airport.

•July 4: Coolest (86 degrees - record) and rainiest (0.78 of an inch - record) Fourth of July in Tucson history.

• Aug. 12-13: Back-to-back, record-setting 109-degree days (the hottest temperatures of the year)

• November: Warmest four-day Thanksgiving weekend on record (average temperature: 67.1 degrees).

Compiled by Kori Rumore with information from the National Weather Service

Contact reporter Doug Kreutz at dkreutz@azstarnet.com or at 573-4192. On Twitter: @DouglasKreutz