Highest temperature in Paris on July 2?

Platform comparison

Market context

The underlying event is the highest temperature recorded at Paris-Le Bourget Airport on 2 July 2026, a date that historically aligns with Paris’s long-term average maximum of 24°C and roughly eight hours of daily sunshine[2]. While the current crowd-implied probability for a specific high-temperature outcome sits at 0%, Polymarket traders are heavily concentrated on 24°C (47%) and 25°C (35%), driven by recent cooling following France’s record June heatwave[1]. This divergence between the 0% crowd line and the 47% Polymarket frontrunner suggests a meaningful gap in how different platforms interpret the post-heatwave temperature drop, even as Météo-France previously forecast peaks of 40°C during the late-June surge that has now subsided[3].

Traders should monitor the immediate weather outlook for the Paris region, particularly any announcements from Météo-France regarding residual warm air influxes from North Africa, which could still push temperatures toward 37°C (99°F) despite the cooling trend[6]. The settlement source is Wunderground data for the Paris-Le Bourget station, so real-time updates from that specific airport station will be the definitive catalyst for resolution, overriding broader regional forecasts[1]. Given that Paris’s record high of 42.6°C was set on 25 July 2019, the current market focus on 24–25°C reflects a cautious consensus that the exceptional June heat has not extended into early July, though any sudden shift in the forecast could rapidly alter the implied probabilities across platforms[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

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

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 UK 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.