Trader consensus on Polymarket heavily favors under 20mm total precipitation for April in London at 67.3% implied probability, driven by exceptionally dry conditions recorded to date—only about 2-3mm accumulated at Heathrow Airport through April 16, versus the 42mm monthly climatological normal from Met Office data. A record warm spell early in the month, peaking at 26.5°C in Kew Gardens on April 8, featured persistent high-pressure subsidence that suppressed cloud development and rainfall. Recent scattered showers added just 2.6mm over the past week, maintaining the deficit. While forecast models indicate potential for light precipitation in the remaining fortnight, ensemble guidance from NOAA and UKMO suggests below-average totals, aligning with historical dry Aprils around 30-40mm amid shifting jet stream patterns post-wet winter. New daily observations and 5-day outlooks will refine probabilities as the resolution nears.