Science · Ordinary People
His grandfather told him stories about the rain prophets. Raul Souza taught a machine to listen.
Raul Victor Magalhães Souza · Jaguaribe Valley, Ceará, Brazil (sertão)
A 16-year-old in Ceará wrote down what six of Brazil's traditional rain prophets watch for, from the flowering of the mandacaru to the brightness of the Sete-Estrelo, crossed it with weather records going back to 1981, and tested the result against a real rainy season.
The person and the place
Raul Victor Magalhães Souza is 16 and studies at a state public high school in Fortaleza, Ceará. The rain prophets he went looking for are in the Jaguaribe Valley, in Brazil's semi-arid sertão.
The problem Raul cared about
In the valley the rainy quarter decides the year, and the rain is not dependable. Water is scarce, the season is uncertain, and drought lands directly on the community that lives there. The people who have read that season locally for generations are the rain prophets, who watch for a lunar halo, the flowering of the mandacaru, a black butterfly, the brightness of the Sete-Estrelo, and call the coming rains from what they see. Raul's grandfather, the farmer Luiz Maia, was his way in. It was his grandfather's stories about the prophets that gave him the idea for the research.
The agency moment
Raul treated the prophets' knowledge as data nobody had bothered to write down, so he wrote it down. Six prophets across five municipalities told him what they watch for, and he turned their answers into ten measurable parameters covering animal behavior, plant signs, and atmospheric conditions. Against those he set the Funceme and Inmet records from 1981 to 2024, more than 40,000 of them. His professor, Helyson Lucas Bezerra Braz, mentored the project, a UFC laboratory partnered on it, and per Diário do Nordeste the two of them built the result into a machine-learning model behind a Streamlit interface.
What changed
They tested the system, Inteligência Artificial dos Profetas da Chuva, against the 2025 rainy season. Between January and March it estimated 422.1 mm of rain; 431.5 mm actually fell, a mean monthly error of 5.7%. For comparison, a commercial reference platform put the same season at 318 mm, off by 30.8%. ABES, which organizes the Brazilian stage of the Stockholm Junior Water Prize, also reports 94.5% accuracy in the model's classification performance, from that one season of validation. The project won the high-school category of Brazil's 31st Prêmio Jovem Cientista, then the Brazil stage of the Stockholm Junior Water Prize. In August 2026 Raul went to the international final in Stockholm during World Water Week as Brazil's representative. "Tenho que agradecer ao meu avô, minha principal referência e base para a construção do projeto," he said. I have to thank my grandfather, my main reference and the foundation for building this project.
The move worth copying
He didn't choose between his grandfather's knowledge and the data. He wrote down what the elders already knew, carefully enough that a machine could learn it. If you know someone whose knowledge lives only in their head, writing it down is the whole first step.
"Tenho que agradecer ao meu avô, minha principal referência e base para a construção do projeto." (I have to thank my grandfather, my main reference and the foundation for building this project.) — Raul Victor Magalhães Souza, ABES
Sources
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Curated by Good in Progress from the public record.
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