Highest temperature in Paris on July 7?

Platform comparison

Market context

The real-world event at stake is the peak temperature recorded on 7 July 2026 at Paris-Le Bourget Airport, a date that historically carries significant heatwave potential. Paris has seen July highs soar to 43°C (109°F) in 2019, with the average daily high sitting at 26°C and the range of extremes spanning 20°C to 43°C over the past three decades[1]. While the current crowd-implied probability for the highest temperature falling in the top range is 0% YES, this consensus likely underestimates the volatility of early July weather in France, where heatwaves have repeatedly exceeded 40°C in recent years[2].

Traders should monitor the arrival of the next extreme heatwave predicted by Météo-France, which is forecast to begin the week of 6 July and persist until 14 July, potentially pushing temperatures well above seasonal norms[2]. Although climatologists warn that precise predictions beyond ten days are impossible, the strong probability of this return to extreme heat suggests the 0% market price may be a value spot for contrarian positions betting on a scorching peak[2]. The key dependency is whether the cooler air from the west fails to reach mainland France, a scenario that would sustain oppressive conditions and elevate the risk of record-breaking highs at the airport station[2].

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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.

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.

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