Recent numerical weather prediction models indicate mild autumn conditions over São Paulo on May 17, driven by a weakening cold front that limits daytime heating while southeasterly winds maintain moderate moisture levels. Ensemble forecasts place the most likely maximum temperature near 22–23°C, aligning with the market’s leading 52.5% implied probability for 23°C or higher and the 23% chance assigned to exactly 22°C. These odds reflect historical May climatology, in which daily highs average 22–24°C, tempered by typical variability from Atlantic sea-surface temperatures and local urban heat-island effects. Updated model runs scheduled for the next 12–18 hours will provide the final guidance before official observations determine resolution.