Highest temperature in Paris on July 12?

Platform comparison

Market context

Paris faces a critical heat check tonight as traders assess the likelihood of record-breaking temperatures at Paris-Le Bourget Airport on 12 July 2026. The current crowd-implied probability for any specific high-temperature outcome sits at 0% YES, yet Polymarket data reveals a stark divergence: the frontrunner outcome is 35°C at 48%, closely trailed by 36°C at 47%[1]. This split between the zero-implied probability on the queried contract and the strong consensus for mid-35s heat highlights a significant pricing inefficiency across platforms, suggesting the market expects a genuine heatwave despite the current odds.

Historical precedents frame this expectation, with Paris recording its highest temperature of 42.6°C on 25 July 2019 during a severe European heatwave[4]. While France’s national record reached 45.9°C in southern Gallargues-le-Montueux recently, mid-July in the capital has consistently produced extremes above 35°C during warm spells[2][5]. The 0% probability currently assigned appears disconnected from this thermal history, where July temperatures in Paris have frequently breached the 35°C threshold in recent decades, making the current odds an outlier compared to established climatic patterns.

Traders should monitor real-time updates from Wunderground, the designated resolution source, for the official high temperature recorded at the airport station[1]. With the settlement window closing at 12:00:00Z tomorrow, the final reading will depend on immediate atmospheric conditions, including cloud cover and wind direction, which are currently showing passing clouds and 15 mph winds as of 23:00 UTC[3]. Any sudden shift in these variables or a Met Office announcement regarding heat alerts could rapidly alter the implied probability, especially given the ongoing European heatwave context that has already pushed temperatures to record levels across the region[5][8].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Paris on July 12? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.