It's not just you: It HAS been cooler in Phoenix this winter, comparatively speaking
Weldon B. Johnson
Bouts of cooler-than-normal daytime high temperatures plus chilly nights near freezing in the Phoenix area have some of us thinking we’re experiencing an unusually cold winter.
But the numbers show that it’s just a case of people having short memories when it comes to weather. Or maybe illustrating the difference between weather (what's happening now) and climate (what we can expect to happen).
You can’t blame them.
Remember last winter, when a couple of 80-plus-degree days set records on Jan. 29 and 30? How about temperatures pushing past 85 by the second week in February 2016?
Phoenix has experienced more than its share of warm winters in recent years, so the cool temperatures of the past few weeks have been a shock to the system.
State climatologist Nancy Selover gets it. She knows what we’ve been going through.
“I was thinking in the beginning of January when we had those freezing temperatures, we hadn’t had that in a few years,” Selover said. “We used to have them all the time, but now, not so much. But the reality is, that was our normal.”
So what is normal?
The average high temperature in Phoenix from Dec. 1 (the start of winter for meteorologists) through Feb. 10 has been 66.3 degrees, according to National Weather Service numbers. The normal high for that period is 67.5, so it has been a little cooler.
But when you look at the average low temperature and the average temperature (taking the average high and low and dividing by two), the numbers get even closer.
The average low this winter has been 45.6 degrees (normal is 45.9) and the average average temperature has been 55.9 (normal is 56.7).
In other words, this has been a pretty middle-of-the-road winter when it comes to temperatures.
Even taking rain into consideration, this winter hasn’t been that unusual.
Average rainfall from Dec. 1 through Feb. 10 for Phoenix is 2.08 inches. So far this winter, the city has recorded 1.32 inches.
And Flagstaff and Tucson have similar stories to tell, Selover said.
“Flagstaff, Phoenix and Tucson, none of them had temperatures or precipitation for the month that put them anywhere near the wettest, the driest, the coldest or the warmest (on record),” she said.
A weak El Niño?
The hoped-for El Niño conditions have been more like El Neutral for most of the winter.
The National Oceanic and Atmospheric Administration didn’t even declare El Niño conditions to have arrived until the Feb. 14 edition of its El Niño Southern Oscillation blog.
El Niño winters can be a big deal around here because they can be cooler and wetter than normal. The wetter part of that deal is what we’re usually hoping for, considering the ongoing drought in the Southwest.
But the current El Niño conditions (which can be identified by warmer-than-normal waters in the eastern equatorial Pacific Ocean) are pretty weak so it’s doubtful they will have much of an impact.
University of Arizona climatologist Mike Crimmins said El Niño hasn’t played much of a role this winter.
“El Niño lurked in the background all fall right up until now, but never really connected with the atmosphere,” Crimmins said via email. “We can’t really connect any of the precipitation we have had in December up until now to (El Niño)."
How much snow did N. Arizona get?
Selover said preliminary reports indicate that snow levels in northern Arizona (where much of our drinking water comes from) have been close to normal, but also inconsistent.
Some areas have reported near-normal conditions while others, such as the White Mountains, have been a little off, she said.
But the ground underneath that snow wasn’t saturated with moisture before the snow fell, so that could have an impact on spring runoff.
“I know in the rest of the Four Corner states they’re having this issue and I can’t imagine why we wouldn’t be because we’re seeing the same things they’re seeing,” Selover said.
“Once we get to the time of snow melt, we might not be looking at recovering as much of that water into the streams and reservoirs as we would hope because some of it is going to soak into the ground.”
What's next for Phoenix weather?
The Climate Prediction Center’s seasonal outlook calls for a 40 percent probability of above-average temperatures for Arizona. It also calls for an equal probability of above- or below-average rainfall.
Crimmins said El Niño probably won’t be much of a factor either way.
“There is an outside chance that El Niño could impact our weather in March, but I think it is way outside,” he said. “It has been weak and not much of a player so far, so it would be tough for it to make much of a difference later in the season.”
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