Recent Met Office and ensemble forecasts position 25–26°C as the leading outcomes for London's highest temperature on September 29, driven by a transient warm southerly flow ahead of an Atlantic low-pressure system that will increase cloud cover and introduce light rain later in the day. Afternoon peaks are expected near 25–27°C under partial sunny intervals, with minimums around 15–19°C, reflecting above-average late-September conditions where the long-term mean high sits near 18–20°C. Model consensus shows modest spread due to variable cloud thickness and wind shifts from the east-southeast, keeping 24°C and 27°C as lower-probability tails while limiting upside beyond 27°C. Updated guidance through the morning will refine exact maxima at official stations.