Highest temperature in Paris on August 21?

Platform comparison

Market context

The market is pricing the likelihood that Paris-Le Bourget Airport will record a maximum temperature of 32°C or higher on 21 August 2026. The crowd has assigned this outcome just 1% implied probability, positioning it as a substantial underdog against cooler temperature ranges.

Paris's August climate sits in a predictable band. Historical data from Le Bourget shows that temperatures exceeding 32°C occur in roughly 15–20% of August days across a typical decade, though frequency varies considerably year to year. The city's all-time August high stands at 40.4°C, recorded in 2003 during an exceptional heatwave. More recently, August 2022 saw multiple days above 35°C, whilst August 2023 remained moderate. The 1% probability suggests the crowd is anchoring heavily to cooler recent precedent rather than accounting for the full historical range of August variability at Le Bourget.

Traders monitoring this market should track European summer weather patterns as they develop through 2026, particularly Atlantic blocking systems and North African heat advection in early-to-mid August. The Copernicus Climate Change Service and Météo-France issue seasonal outlooks that often signal whether conditions favour warmer or cooler-than-average periods. Any indication of a persistent high-pressure system over continental Europe in late August would shift the calculus materially. The resolution hinges on the Daily Observations table at Weather Underground rather than summary figures, making instrument accuracy at Le Bourget itself a minor but genuine dependency worth noting for settlement purposes.

Methodology

We track Highest temperature in Paris on August 21? 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 Who Will Win 2026. 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 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.

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.