Recent dry conditions across southern England through mid-May, following a notably arid April, have anchored trader sentiment toward below-average precipitation totals for London in May 2026. Official Met Office guidance and ensemble models indicate a transition to more settled high-pressure patterns for the latter half of the month, limiting opportunities for widespread rainfall despite occasional showers. Historical climatology places May averages near 50 mm at Heathrow, yet current observational data and short-range forecasts suggest the final monthly sum will likely fall in the 15–30 mm range. Model disagreement on the timing and intensity of any Atlantic fronts introduces the primary uncertainty distinguishing the closely matched 15–20 mm and 25–30 mm outcomes.