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is a climatologist with the University of ÃÛÁÄÖ±²¥â€™s Department of Environmental Science and an investigator for the National Oceanic and Atmospheric Administration’s program, a Tucson-based regional collaboration between the U of A and New Mexico State University.

Unfortunately, he said, there are no easy answers — not even for people like him — when it comes to the Sonoran Desert’s all-important summer rains.

While it’s tempting to blame things like extended drought or climate change for the disappointing precipitation totals so far, Crimmins said the only predictable thing about the monsoon seems to be its lack of predictability.

“I've been musing about this and trying to make sense of it,� he said. “I've been here in Tucson for 25 years now, and I've decided that there are no twinsy monsoon seasons. None of them ever look like each other. Rarely do they even look like close cousins.�

As of noon on Friday, Tucson’s summer rainfall total stood at just 1.94 inches, well below the long-term average for this point in the season. “We should have about twice that for mid-August,� Crimmins said.

Roughly 70% of the monsoon precipitation recorded so far came from a single overnight storm that dumped 1.35 inches on the official weather station at Tucson International Airport on July 15 and 16.

If the season ended Thursday night, it would rank as the third-driest on record in the Old Pueblo. “I don't think there's really been a good side of town this year, so I think there's a lot of shared misery for Tucsonans,� Crimmins said.

The rest of ÃÛÁÄÖ±²¥ has been suffering, too. As of late last week, remained well below average across the state and were especially bleak in places including Phoenix, Gila Bend, Yuma and Ajo.

But the picture begins to improve the farther east you go.

“If you drive I-10 out of town, it gets a little better in southeastern ÃÛÁÄÖ±²¥,â€� Crimmins said. “By the time you get to Deming, New Mexico, they're in a real honest-to-goodness good season over there. I’ve heard people in Las Cruces talk about how wet it has been and how it’s the best monsoon they've seen in a long time.â€�

Confidence low

Monsoon season in the Southwest officially begins on June 15 and lasts through September.

In a good year, Crimmins said, that period will be dominated by a large high-pressure system anchored over the Four Corners area, creating a clockwise flow from the south and east that draws in moisture from the Gulf of Mexico and Gulf of California.

So far this season, though, that high-pressure system has sagged well to the south, near the U.S.-Mexico border in New Mexico and southeastern ÃÛÁÄÖ±²¥, a pattern that often results in dry air being drawn into much of ÃÛÁÄÖ±²¥ instead. “It’s why the Dragon Bravo Fire (at the Grand Canyon) has continued to burn well into August,â€� Crimmins said.

Earlier this year, forecasters were predicting a wetter-than-normal monsoon season for Tucson and elsewhere, but that optimism quickly faded, in part because of an unusually cool, wet weather pattern in late spring that defied expectations.

“You even saw that the (federal) Climate Prediction Center just totally backed away from that in June and said, ‘We have no idea,’� Crimmins said. “They issued an equal-chances forecast for the summer, and that was smart, because they weren't sure and I wasn't sure.�

And it’s like this almost every year, he said.

“I’ve been here for a while now, and I don't think I've seen a season where we went into it with a great deal of confidence (about) how it would turn out. We've had so many surprises.�

Take 2020 for instance: Tucson saw just 1.62 inches of monsoon rain, the second-lowest total since recordkeeping began in 1895, en route to its driest year on record. “We had no idea that we were heading into that kind of misery,� Crimmins said.

Climate forecasters were just as surprised the following summer, when Tucson racked up well , including 8.06 inches in July alone, the all-time record for a single month.

“I was thinking maybe this year was like 2020, but it's not,â€� Crimmins said. “2020 was really bad across the entire Southwest, ÃÛÁÄÖ±²¥ and New Mexico. This one's got a different flavor, where it's very bad across ÃÛÁÄÖ±²¥ but not really across most of New Mexico. So it's like another variation on the theme.â€�

As for , he said, it is “everywhere all the time,� so it is almost certainly having some influence over the monsoon season in the Southwest. Scientists just can’t say what that might be yet.

“We don't know which direction it’s going. It's not systematic right now of a shift either dryer or wetter or even more extreme or less extreme, but the assumption is that something’s going on for sure,� Crimmins said.

Betting on rain

He doesn’t expect the answers to come anytime soon, either.

“I think it's still going to be a mess teasing out the climate change signal in the monsoon for a long time. We're just going to have to see a bunch of different seasons play out, and then try to do those attribution exercises to see how bigger, broader hemispheric shifts have influenced the season from one to the next,� Crimmins said.

One likely impact is already easy enough to see in the data and feel on your skin: Summers are hotter here than they used to be. “We're seeing that in all the records we broke a week or two ago and in the overnight temps that are higher,� Crimmins said. “I think the climate change fingerprints on the season are gonna be more on the temperatures than on the precip.�

Of course, he could turn out to be wrong about that. Trying to figure out the monsoon can make even the experts look like amateurs. (For proof, look no further than the mediocre performances turned in so far by Crimmins and his fellow climate researchers in the annual they opened up to the general public in 2021.)

“You start playing these weird emotional games in your head like, ‘Last year was bad, so Mother Nature owes us a good one,’� Crimmins said with a laugh.

Think of it as a way to “reason with unreasonable things,� he said, even if it does make him sound like a sad-sack gambler, convinced his luck is about to change.

After all, monsoon season isn't over yet. Maybe all it takes to make things better is to talk about how lousy it's been so far.

Since Crimmins’ conversation with the Star, the forecast has been filled with promising numbers followed by percent signs, peaking this coming Tuesday when the  says showers and thunderstorms are likely across most of the valley.

“Next week looks pretty good, but then I've thought that every week this summer,� the climatologist said. “Now I'm sorry I even said it out loud, so I'll take that back.�