Highest temperature in Paris on July 20?

Platform comparison

Market context

On 20 July 2026, Paris-Le Bourget Airport will record its highest temperature for the day, a single real-world data point that determines how this prediction market settles. In prediction markets, a YES share pays out if the event occurs, while a NO share pays out if it does not; the current price of each share represents the crowd’s implied probability. Here, the market currently assigns 0% probability to the YES outcome, suggesting traders believe the temperature will fall outside the specific range tied to that option.

Historically, July is Paris’s hottest month, with average highs of 25–27°C, but heatwaves can push temperatures to 35–40°C for several days, especially in mid-July [1]. Recent forecasts for July 2026 warn of an intense heatwave in Paris, with temperatures expected to soar between 36°C and 39°C, and some models suggesting a possible peak near 40°C [3]. This aligns with the current Polymarket frontrunner of 24°C at 100%, indicating the crowd expects a warm but not extreme day relative to the heatwave peak [2].

Traders should monitor daily weather updates from French meteorological services and real-time forecasts for Atlantic air movements, which could bring cooler conditions by the end of the week [3]. The settlement relies on Wunderground’s recorded highest temperature for Paris-Le Bourget Airport on that specific date, so any official revisions to the station’s data would directly impact resolution. No announcements or schedules are pending beyond the natural progression of the forecast, making daily temperature checks the primary catalyst for probability shifts.

Sources: 1 · 2 · 3 · 4

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

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 Prediction Market UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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'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.

Do I need to KYC for this market?

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