Highest temperature in Paris on August 4?

Platform comparison

Market context

Paris is ending up with a **mid-30s Celsius** kind of day by the look of the market, but the contract settles on the single highest reading at Paris-Le Bourget Airport, so the relevant question is whether the station nudges into the 33°C to 35°C band rather than simply how warm the city feels broadly. Polymarket’s crowd currently has **31°C** leading at **35%** and **32°C** close behind at **34%**, while the contract still shows **0% YES** at the far less likely tail outcomes, which implies the market sees a modest peak rather than a runaway heat spike.[3]

That pricing sits below the sort of August climatology that usually centres Paris in the low-to-mid 20s Celsius, but recent summer extremes show why traders cannot lean too hard on averages. Reuters reported in June that France’s weather agency was seeing temperatures hitting record highs, and AP noted the country’s hottest-ever day in that same early-summer heat episode, underscoring that the top end of Paris temperatures can still break out sharply when a heat dome develops.[16][17] In practical terms, a forecast in the low 30s would make the 31°C and 32°C buckets credible, while anything above 34°C would require a stronger-than-expected afternoon spike at the airport station.[2][9]

The main catalysts are ordinary but important: the daytime forecast evolution, any late-day convective cloud or rain, and whether the airport’s maximum is reached before cooler maritime air arrives. Because the contract resolves from Wunderground’s Paris-Le Bourget history page, traders should watch the station-specific high rather than city-wide forecasts or central-Paris headlines; the crowd-implied probabilities can diverge from broader weather commentary when the airport sits a degree or two cooler or warmer than the urban core.[3]

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

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 Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.