Monsoon Madness: Professional and Amateur Forecasters Invited to Bet on Much-Needed Rain

Lightning in the sky over a building

Lightning strikes behind Old Main on main campus during a monsoon storm.

Chris Richards

Every summer, the people who call the Southwest home can only talk about two things: the heat  and the monsoon.

After an abysmally dry monsoon and a rainfall total of a mere 4.17 inches at Tucson International Airport, 2020 went in the books as the city's driest year on record. Even thirsty saguaros have sprouted blooms in unusual places, signaling distress. The region's people and other ecological natives are also desperately hoping a phenomenal monsoon will bring reprieve.

Unfortunately, there's no guarantee. According to University of Arizona climatologist Michael Crimmins and the National Weather Service's Climate Prediction Center, there are equal chances that monsoon rainfall this summer will be above, at or below the average of 6.08 inches of rain.

"It's basically a scientific shrug at this point," said Crimmins, who also is a professor and Cooperative Extension specialist in climate science.

But, the self-described optimist said there is hope: "Two extreme years are unlikely, so my expectation is for more typical rainfall this year."

The monsoon officially starts June 15 and ends Sept. 30.

"The most common climate question I am asked in June is 'What's the monsoon going to be like this year?'" said Zack Guido, an assistant research professor at the Arizona Institutes for Resilience.

With the monsoon capturing the attention of scientists and the public, Guido, Crimmins and their colleagues Ben McMahon and Rey Granillo, also at AIR, developed a game that allows people to test their own knowledge of the monsoon by making predictions: Southwest Monsoon Fantasy Forecasts. Guido is the principal investigator for the project, which is a study that uses a game to promote climate awareness and evaluate public forecasting skills. Players complete a short questionnaire about their monsoon experience and history before making their predictions.

"Mike (Crimmins), myself and colleagues at CLIMAS have been talking and writing about the monsoon for over a decade," Guido said. "And every single year, it's the climate phenomenon that captivates people in the Southwest. It's incredible on many levels: It's visually stunning, it's hazardous, it's a break from the heat, it's water for our ecosystem and it connects people."

How to Play

The game draws inspiration from fantasy sports. A week before the first day of July, August and September, players will estimate the total monthly precipitation as a percentage of the historical average at each of the five major cities in the U.S. Southwest monsoon region: the Arizona cities of Tucson, Phoenix and Flagstaff plus Albuquerque, New Mexico, and El Paso, Texas. In total, players will make 15 estimates and earn points based on the riskiness and accuracy of their estimates. The goal is to accumulate the most points over the three-month period.

So, for example, you might guess that Tucson will receive 50% of the historical average for July. That month's average is 2.21, which means that about 1.1 inches would need to fall for you to win full points for the guess.

"If you think Tucson will receive 200% of average rainfall – which historically happens infrequently – and end up being right, then you get more points than a guess that is closer to average. It's like betting on the underdog," Guido said.

But if you get a "bull's-eye," he said, you get all the points.

"It's exceedingly unlikely you'll get a perfect guess, so our accuracy scoring is tiered," he explained. "The closer your estimated forecast is to reality, the more points you get. The accuracy tiers change by station and month based on the historical records of each site."

Players can sign in on the Southwest Monsoon Fantasy Forecasts website to make their forecasts and learn more details. When you click "sign in," you will be prompted to sign in via Google.

"It's important to note that we're not trivializing the monsoon," Crimmins said. "It's critically important to our ecosystem, agriculture and more. I like to think of the fantasy monsoon as an outlet for our stress and an expression of our reverence surrounding this time of year." 

The goal is to encourage engagement surrounding the monsoon. The team also wonders if the game can be used as a teaching tool in classrooms.  

"The other thing we're interested in understanding is whether or not the sort of experience people have with the Southwest monsoon allows them to be better forecasters than some of our technical models out there," Guido said. "We hypothesize this is not the case, but we're still curious. What interests me most is generating enthusiasm around this time of year to increase education in STEM and climate."

Good Luck and Here's Hoping

Team members hope this is just the first year of many years of playing Monsoon Fantasy. So, if you don't win this year, you'll have more chances. They know this isn't easy.

"Everyone is kind of interested in predictions, but none of them are good," Guido said. "This is for a whole bunch of reasons, but mostly because the monsoon is a complicated phenomenon that makes our scientific ability to predict it really low. It's really not better than flipping a coin."

One of the reasons the monsoon is so hard to predict is a function of geography.  

"The monsoon's central activity is in Mexico. The American Southwest is on the northern periphery of it, where variability reigns," Guido said.

Another reason monsoons can be difficult to predict is that these storms typically occur in small, short, isolated outbursts. Many lower-resolution forecasting models are unable to predict such storms with high accuracy, according to Crimmins. 

Often, people will try to draw conclusions about the monsoon based on sea surface temperatures in the Pacific Ocean. But sea surface temperatures are more predictive of winter rainfall, rather than the monsoon. Above-average sea surface temperatures, more common in El Niño climate patterns, typically bring more winter rainfall, while La Niña, characterized by cool sea surface temperatures, brings dry winters.

"It's so humbling how we just don't totally get the monsoon," Crimmins said. "The forecasting is so hard, and I don't even know how it can get better. That's why the Monsoon Fantasy game is so cool – it's more like a test of people's emotional state and hopefulness."

As a climatologist, Crimmins said his guesses will ride the middle: "At least average amounts of rain this year is important. If it's dry again, there could be problematic outcomes."

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