Pronóstico: Highest temperature in Paris on July 20?

Platform comparison

Market context

Paris-Le Bourget recorded its highest temperature on 20 July 2026 as 24°C, a figure that aligns with the market’s frontrunner outcome now pricing at 100% on Polymarket. The contract, settled in USDC on Polygon via conditional tokens, reflects a crowd-implied probability of 0% for any higher range, effectively closing the door on heatwave scenarios for that specific date. This pricing contrasts sharply with early July forecasts that warned of orange or red heat alerts, with temperatures projected to reach 35–40°C across the city [3].

Historical July data shows average highs of 25–27°C, but canicules have previously pushed peaks to 35–40°C for multiple days, especially mid-month [2]. The current 24°C reading sits just below the seasonal average, suggesting the intense heatwave forecast for early July either failed to materialise on 20 July or was interrupted by cooler Atlantic air, as forecasters had predicted relief by the end of that week [4]. Traders should note that Wunderground’s resolution source will capture the single highest reading for Paris-Le Bourget, making outlier spikes critical even if daily averages remain moderate.

Key catalysts to monitor include Meteo-France’s official alert updates and any late-season shifts in Atlantic airflow, which could alter temperature trajectories if the settlement window were extended. However, with the window ending 2026-07-20T12:00:00Z and the event already past, the market has locked in the observed outcome. The 0% probability on higher ranges now serves as a definitive post-event confirmation rather than a predictive signal, reflecting the on-chain mechanics’ finality once the real-world data is ingested.

Sources: 1 · 2 · 3 · 4

Methodology

We track Pronóstico: Highest temperature in Paris on July 20? 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

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Qué Es trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.