Highest temperature in Paris on May 31?

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Market context

The settlement hinges on the single highest temperature recorded at Paris-Le Bourget Airport on 31 May 2026, with the crowd currently pricing all temperature ranges at zero probability—an artefact of the market's recent opening rather than genuine consensus that no heat will occur.

Historical data from Le Bourget shows late May temperatures typically range between 18°C and 26°C, with occasional peaks above 28°C during warm spells. The station's records indicate that temperatures exceeding 30°C on 31 May are rare but not unprecedented; the airport recorded 31.5°C on 31 May 2020. Spring weather patterns across northern France have shown increasing volatility over the past decade, with late-May heat waves becoming more frequent though still concentrated in June and July. The current zero-probability pricing reflects insufficient liquidity rather than meteorological certainty.

Traders should monitor European weather models from mid-May onwards, particularly the ECMWF and GFS forecasts which typically gain reliability 10–14 days ahead. High-pressure systems tracking northward from the Mediterranean or Atlantic blocking patterns could drive temperatures into the upper 20s or low 30s. The UK Met Office's seasonal outlook and Météo-France's official forecasts, released progressively through May, will provide the most reliable guidance for Le Bourget conditions. Any early-season heat dome affecting western Europe in late May would shift probabilities substantially, as such systems often persist for several days.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Is this market available outside the US?

Who Will Win is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on Who Will Win?

Zero. Who Will Win routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.