Highest temperature in Paris on August 4?

Platform comparison

Market context

Paris-Le Bourget Airport is the settlement point here, so the key variable is the day’s maximum temperature by noon UTC rather than the general feel of Paris. That makes the market a straightforward max-temperature read, with a narrow time window and a source-specific outcome that can differ slightly from central Paris readings.

The 0% crowd price implies traders see almost no chance of a high enough reading to move the final band, but the recent pattern in Paris points the other way when the city sits under warm late-summer air. Recent forecast coverage for 4 August suggested highs around 25–32°C across Paris and Île-de-France, with one local bulletin calling for sunshine after early showers and highs near 30–32°C. That leaves the market exposed to the exact airport station outcome, where a couple of degrees can decide whether the max lands in a lower or higher bucket.

For a programmatic setup, the useful checks are the station forecast, the latest model run, and any short-term weather alerts before the 12:00Z cut-off. Early-morning showers, frontal timing, and cloud break can all shift the peak into or out of the settlement band, so conditional orders should be tied to the latest observation feed rather than a blanket Paris headline. The practical trigger is whether the Le Bourget maximum can be confirmed quickly enough before the window closes.

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

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 Polymarket Bot 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.

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.

Do I need to KYC for this market?

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