Zeus: A Settlement-Aware Engine for Daily-Temperature Prediction Markets
Prices Polymarket's daily-temperature markets from ECMWF-anchored multi-model forecasts, integrating over each contract's exact settlement rule — station, observation clock, rounding and bin topology — and grades every decision-time probability against verified settlement in a published calibration report.
Each daily-temperature contract turns a city's weather, a settlement station, an observation convention, and an integer rounding rule into a family of mutually exclusive claims. A forecast can be meteorologically accurate and still lose because it prices the wrong station, the wrong preimage of a rounded bin, or a book that cannot fill at the assumed cost. The engine therefore treats understanding as a chain of proof. It records what evidence existed before the decision, turns the forecast into one probability distribution over the complete settlement space, maps each executable route to its actual payoff, and commits only when the lower tail of that decision remains useful after depth, fees, and existing exposure. Settlement judges the exact belief the system committed to — not a more favorable story reconstructed afterwards.
