Recent Met Office forecasts for London point to overnight minimum temperatures of 17–18°C on June 19, driving the near-even market split between those two outcomes amid a transitional weather pattern. A building ridge of high pressure across southern England is promoting clearer skies and reduced cloud cover, which allows for greater nocturnal radiative cooling under light winds, while daytime maxima are projected to reach 26–29°C. Ensemble model guidance shows limited spread in low temperatures due to stable synoptic conditions, though small variations in wind speed or residual humidity could shift the minimum by 1°C. Historical June climatology for central London places average overnight lows near 12–14°C, making the current outlook mildly above normal and keeping probabilities for 16°C or lower subdued. Updated model runs and official guidance expected in the next 24 hours will likely refine the exact threshold ahead of market resolution.