Highest temperature in Paris on July 17?

Platform comparison

Market context

Paris-Le Bourget Airport is set to record its peak temperature for 17 July 2026, with the settlement window closing at noon UTC tomorrow. The specific contract resolves to the Celsius range containing the day’s highest reading at this station, sourced directly from Wunderground history.

Historical mid-July heat in Paris typically clusters between 24°C and 28°C, making the current 0% implied probability for any outcome above 27°C a stark divergence from the 92% crowd-implied chance assigned to the 26°C range on Polymarket [1]. This suggests traders are pricing in a notably mild day, contrasting with analyst consensus that often anticipates temperatures closer to 27°C or 28°C during this period. The near-zero odds for higher ranges indicate a strong belief in cloud cover or Atlantic airflow suppressing the heat, a view that stands out when compared to broader weather forecasts for the region.

Traders should monitor the 00:00 UTC European weather model updates and the 12:00 UTC Met France daily forecast, which will confirm cloud density and wind direction before the settlement deadline. A sudden shift in the Atlantic jet stream or an unexpected heat dome from the south could invalidate the current pricing, particularly if the 26°C frontrunner fails to hold as real-time station data emerges [1]. No major announcements are scheduled, but the dependency on Wunderground’s final daily aggregation means the market remains sensitive to the last few hours of afternoon readings before the 12:00 UTC cutoff.

Sources: 1

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.