Recent Japan Meteorological Agency forecasts highlight a persistent high-pressure ridge over the Kanto Plain driving southerly warm advection and clear to partly cloudy conditions, positioning the official Otemachi maximum near 28–29°C for May 17. This setup aligns with mid-May climatology where daily highs typically range 22–25°C but can exceed that under strong insolation and light winds that limit mixing. Trader sentiment splits closely between 28°C and 29°C because ensemble models show minor variations in afternoon boundary-layer heating and cloud timing that could shift the peak by one degree, while the modest 19% probability on 30°C or higher reflects limited potential for further warming if the ridge strengthens unexpectedly. Official resolution will hinge on the verified whole-degree maximum reported by JMA at day’s end.