Highest temperature in Paris on August 4?

Platform comparison

Market context

Paris has not shifted into a heatwave pattern, but the latest forecasts still point to a warm afternoon with some spread between models: one source has highs around 25-26°C with patchy rain possible, while another puts the day nearer 30-32°C after morning showers and thunderstorms clear.[2][13] That matters because this market settles on the *day’s maximum* at Paris-Le Bourget Airport, so a short-lived spike can move the result even if the rest of the day is milder.

Historically, early August is one of Paris’s warmer periods, with average highs clustered in the mid-20s Celsius and 4 August often near the seasonal peak.[1][11][12] The crowd’s 0% YES pricing suggests the board is treating a much hotter outcome as extremely unlikely, but the spread in public forecasts means traders are still watching whether the upper end of the range can be reached. In comparable Paris August conditions, outcomes usually land in the mid-20s unless stronger sunshine or continental air pushes temperatures higher later in the day.[1][11][12]

For traders, the key catalysts are the afternoon temperature trajectory, cloud cover after any morning showers, and whether the airport station warms more quickly than city-centre forecasts imply.[6][13] The resolution source is Wunderground’s Paris-Le Bourget history page, so the final print depends on that station’s observed maximum rather than the broader Paris forecast.[market description] Any late-day clearing, unexpected convection, or a stronger-than-expected warm sector would be the main route to an upside surprise.

Sources: 1 · 2 · 3 · 4 · 5

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 Today. 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.

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.

Do I need to KYC for this market?

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