Traders see the 50-80 mm range as most likely for June 2026 London precipitation because historical averages hover near 43-60 mm while early-month observations already show roughly 51 mm by mid-June, placing the running total slightly above normal. Mixed long-range signals from the Met Office and other models—some favoring drier conditions under building high pressure and others pointing to near-average or wetter outcomes amid a changeable Atlantic jet stream—create genuine uncertainty over remaining weeks. Key variables include the frequency of frontal systems, potential for convective showers in warmer air masses, and steering patterns that could add or withhold 10-20 mm. This balance of partial data, climatological baselines, and diverging forecasts supports the tightly clustered market-implied odds across the central bins.