Magic of the monsoon: A 'socially and ecologically' important phenomenon for the Southwest

Clouds and lightning over a desert landscape

The monsoon officially runs June 15 to Sept. 30 and brings an average of 5.69 inches of rainfall to the arid southwestern United States.

Zack Guido

The National Weather Service's Climate Prediction Center is forecasting a drier than average monsoon this year in the southwestern United States, where summer monsoon rainfall typically averages 5.69 inches.

But there's always a chance, even if slim, that the season's forecast could lose out to wetter weather.

University of Arizona climate scientists Michael Crimmins and Zack Guido meet before and throughout the monsoon to discuss the official forecast and debate their own predictions on their CLIMAS podcast, like sports reporters dissecting a game. 

For the fourth year, they are also hosting Monsoon Fantasy Forecasts, a game inspired by March Madness or fantasy football in which desert dwellers – or anyone around the world with an internet connection – can bet on the amount of rainfall that each month of the monsoon will bring to different cities throughout the Southwest. 

Over 500 people placed bets online last year. This year's iteration of the game introduces a new element: The worldwide leaderboard will still track the best performing predictions overall, but now, players can invite friends into specific online groups to compare scores outside of the main leaderboard.

The monsoon officially runs from June 15 to Sept. 30. Monsoon Fantasy Forecasts players have until the last day of June to place their rainfall estimates for July, the first full month that the game tracks. Predictions for August must be submitted by the end of July, and guesses for September are due by the end of August. First, second and third-place winners will be announced at the end of the season and will earn a $300, $200 and $100 Amazon gift card, respectively. There will also be a winner announced at the end of each month, and they will each earn a $100 Amazon gift card. The same player can win monthly and seasonal prizes, and all prizes will be dispersed in October.

Crimmins, a professor in the Department of Environmental Science and climate science extension specialist for Arizona Cooperative Extension, and Guido, an associate research professor at the Arizona Institute for Resilience and director of AIR International Resilience Lab, talked to University of Arizona News about the official forecast, their predictions and the significance of the monsoon.

Michael Crimmins

Michael Crimmins

Q: What do official forecasts say, and how do they sway your own predictions for the season?

Crimmins: There are many different groups – five in North America and a few in Europe – that make models about how the monsoon will go. The best thing, of course, is to look at all of them. This year, they're all saying the same thing. We should expect a drier – and hotter – next few months. Zack (Guido) is impressed by this, but I'm not. (Laughs.) My gut feeling is they're probably all wrong, which is totally irrational and chaotic.

Q: Does the heat dome that we've all been hearing so much about play a role in this?

Crimmins: A heat dome is just a colloquial term for a high-pressure system in the upper levels of the atmosphere, and it's the same pattern that keeps the monsoon at bay every year and that we have to overcome to get the moisture that brings the first storms. It's also called the "four corners high." But the way the heat dome is really being discussed right now is to describe high-pressure systems in somewhat unusual spots where it's driving really high surface temperatures.

Last year, for many different reasons including climate change, the high-pressure system got stuck in kind of a bad spot, which led to hotter-than-average temperatures and a delayed monsoon for us here in Tucson. 

Q: How does the 2024 monsoon prediction stack up to past years?

Crimmins: Over these last four years, we've had quite a bit of whiplash between really wet years and really dry years; 2020 was historically dry, but forecasts were up in the air in terms of their predictions. Then, we had two seasons back-to-back that were really wet. In fact, July 2021 was the wettest month ever on record in Tucson. Last year, we had another really dry season. In some places, it was even drier than 2020. I think this context adds an element of intrigue to where we're headed this year.

Zack Guido

Zack Guido

Q: Why do you host the Monsoon Fantasy Forecasts game?

Guido: We're trying to bring the enjoyment that we have in thinking about the monsoon to other people and allow them to test their knowledge. We don't actually think that any one person is able to predict the monsoon consistently with a great degree of accuracy, but it sure makes for a good challenge. 

We don't have any data to back this up yet, but we hope that this game encourages people to seek out more information about the monsoon than they otherwise would, and through the inclusion of official resources on the game's website, we think it could influence information-seeking behaviors and learning.

The monsoon is also both socially and ecologically a really important phenomenon for the Southwest. It brings an identity to this area, and people really rally around it in a unique way. Everybody is excited about when it will start, and they talk about it very fondly. Severe weather is captivating. It's just aesthetically incredibly beautiful, but it's also not too severe. It also brings relief to the temperatures.

Crimmins: The monsoon has this weird cinematic buildup. The sun gets higher every day, and then it starts to get hot, but it's still dry. In June, the sun gets higher, the days get longer, it gets hotter, but then the humidity comes in. Tension builds right up to the point where it's almost unfair, and then it rains.