Forecast models from agencies like the Japan Meteorological Agency indicate variable cloud cover, scattered showers, and moderate southerly flow over Tokyo as the baiu rainy season transitions toward summer conditions, keeping the June 26 maximum temperature centered near the 26°C climatological average. This produces closely matched market probabilities across 25–27°C outcomes, with differentiation hinging on exact timing of any frontal passage or diurnal heating under partial sunshine versus persistent moisture. Historical June variability shows highs fluctuating 3–4°C day-to-day due to these factors, while ensemble spreads in current runs highlight genuine uncertainty that new 48-hour model updates could readily shift. Traders appear to price this scientific ambiguity directly into the tight distribution.