Pronóstico: Highest temperature in Paris on July 7?

Platform comparison

Market context

Paris is bracing for an intense heatwave on 7 July 2026, with forecasters predicting peak temperatures near 41°C at the Paris-Le Bourget Airport Station, a figure far exceeding the seasonal average of roughly 25.7°C[1][9]. This extreme scenario directly contradicts the current crowd-implied probability of 0% for the highest temperature reaching the 35°C threshold, suggesting a significant mispricing in the market. Historical precedents from early July 2026 show similar red-alert conditions across northern France, where daytime highs regularly breached 38°C and overnight lows remained above 25°C, limiting any cooling relief[3][4].

The on-chain mechanics of this Polymarket contract, settled in USDC on the Polygon network via conditional tokens, hinge entirely on the Wunderground data feed for the specific station, making the timing of the official daily report the critical catalyst for traders. While the heatwave is forecast to persist for seven to ten days, the immediate dependency is the confirmation of the 41°C peak before the settlement window closes at 12:00 UTC on 7 July[1][3]. Traders should monitor the Meteo France red alert updates and any potential late-week storm developments, which offer a small chance of relief but are unlikely to drop temperatures below the 35°C mark before the deadline[1][3]. The market currently prices a 36.5% chance of the peak hitting exactly 35°C, yet the prevailing meteorological data points decisively toward a higher range[5].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Pronóstico: Highest temperature in Paris on July 7? 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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Polymarket Qué Es. 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.