Highest temperature in Paris on July 7?

Platform comparison

Market context

The real-world event in question is the highest temperature recorded at Paris-Le Bourget Airport on 7 July 2026, a date still three years ahead yet already framed by traders as a potential heatwave peak. While one prediction market lists the current crowd-implied probability for a "Yes" outcome at 0%, Polymarket’s active contract shows a 56% chance that the peak will hit 33°C, with 34°C as the next likely outcome at 26%[1]. This stark divergence between platforms suggests either a liquidity gap or a misalignment in how each market interprets the underlying meteorological risk.

Historical July weather in Paris typically sees daily highs between 74°F and 77°F (23–25°C), rarely exceeding 88°F (31°C), though Le Bourget’s 2026 forecast projects highs up to 99°F (37°C)[3][5]. Recent prediction markets for 5 and 6 July show 29°C and 34°C as frontrunners respectively, indicating a rapid temperature climb already anticipated by traders[2][4]. The 53% probability assigned to a Paris heatwave (≥35°C for three consecutive days by 31 July) further supports the view that extreme heat is plausible, making the 0% "Yes" probability on the other platform an outlier[6].

Traders should monitor the European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal outlook updates and any national heatwave alerts from Météo-France, as these will shape short-term temperature expectations. The settlement relies on Wunderground’s daily record for Paris-Le Bourget, so any data gaps or station recalibrations could affect resolution[1]. With the forecast window open until 2026, volatility in odds is expected as climate models refine their projections, particularly if early summer trends in 2025–2026 deviate from historical norms.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Paris on July 7? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

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 PolyGram. 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 fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.