Current ensemble forecasts from the Met Office and European Centre for Medium-Range Weather Prediction place London's maximum temperature on May 19 near the seasonal mid-May average of 16–18 °C, producing closely matched market-implied probabilities for 17 °C and 18 °C. Light southwesterly flow and partly cloudy conditions are expected to limit daytime heating, while modest uncertainty in cloud cover and boundary-layer mixing keeps the spread between 16 °C and 19 °C narrow. Recent model runs show tight clustering around these values, with resolution hinging on the official observation at London City Airport; any increase in solar insolation could push the high toward the upper end of the favored range.