Forecast models from the Japan Meteorological Agency and global ensembles show Tokyo under persistent cloud cover with light winds and possible drizzle on September 27, limiting solar heating and supporting a maximum of 24°C. This aligns with seasonal norms near 26–27°C yet moderated by the current synoptic pattern, producing the market’s near-certain 24°C outcome at 99.7% implied probability. Traders have priced in the consensus forecast range, with minimal dispersion across model runs. Only an unexpected rapid clearing or stronger southerly flow could push readings to 25°C or higher, while heavier rain would more likely cap the peak below the leading outcome.