Recent Met Office and station data show London has recorded only about 23 mm of precipitation through September 24, roughly half the long-term average, amid predominantly dry high-pressure conditions and just 12 rain days. Forecasts for the final days indicate modest totals of 10–15 mm from scattered showers, primarily late in the period, keeping the monthly sum most likely in the 30–40 mm band. This limited late-month rainfall stems from transient Atlantic fronts rather than persistent wet patterns, supporting the strong market weighting toward the 30–40 mm outcome while leaving room for modest upside if models underperform.