**Forecasts from the Hong Kong Observatory and supporting models indicate a minimum temperature of 25–26 °C for June 15, 2026, driven by an active southwest monsoon and a persistent trough of low pressure.** These conditions are expected to deliver widespread cloud cover, occasional heavy showers, and squally thunderstorms throughout the day and night, which maintain high humidity and limit nocturnal radiative cooling. Official guidance lists a daily range of 26–29 °C, with the overnight low most often projected near 25–26 °C, consistent with typical June climatology under disturbed monsoon flow. Traders have concentrated probability on 25 °C and 26 °C (combined >63 %) because recent multi-model runs and the HKO’s 9-day forecast show little deviation from this narrow band, while the risk of clearer skies or stronger winds that could drop the minimum to 24 °C or below remains secondary. Seasonal outlooks for above-normal temperatures provide background context but are overridden locally by the current synoptic setup. The market will resolve to the lowest official reading recorded by the Observatory on the calendar day, so any late forecast adjustments to overnight cloud or rainfall intensity could still shift the final outcome within the 24–27 °C window.