Recent dry conditions across southern England have kept cumulative May precipitation in London well below the 45–57 mm climatological average through mid-month, with multiple days recording zero measurable rainfall under persistent high-pressure influence. This setup has favored the closely matched 10–15 mm and 15–20 mm bins, as limited Atlantic fronts and suppressed convective activity reduce the likelihood of significant accumulations in the remaining two weeks. Ensemble guidance shows only modest shower potential tied to weak troughing, keeping totals most probable in the lower ranges while still allowing for occasional light rain that could nudge the final figure slightly higher. Met Office model runs and updated outlooks through late May will be the next key inputs for traders monitoring these thresholds.