Recent forecasts from Brazil’s National Institute of Meteorology project a daytime maximum of 22°C in São Paulo on May 17 under typical mid-autumn subsidence, light easterly winds, and modest cloud cover that limits additional solar heating. This aligns with the city’s climatological average high near 22°C for the period and with current model consensus from official stations, keeping the market-implied odds overwhelmingly concentrated on that exact outcome. Historical data show limited day-to-day variability in late autumn, yet any unexpected reduction in afternoon cloudiness or a temporary wind shift could allow a brief spike toward 23°C before resolution.