Tokyo's late-June climate falls under the influence of the East Asian rainy season (tsuyu), characterized by persistent cloud cover, high humidity near 80%, and reduced overnight radiative cooling that typically holds minimum temperatures in the 18–23°C range. With the June 27 low now two days out, ensemble models from agencies like the Japan Meteorological Agency show limited spread, centering on 20–23°C amid variable light winds and possible light rain that moderates cooling. The closely bunched market probabilities around 21–24°C reflect this narrow forecast uncertainty, where even modest shifts in cloud thickness or timing of any showers could alter the recorded minimum by 1–2°C. Historical June lows in Tokyo average near 20°C, providing a baseline traders weigh against current model consensus.