Highest temperature in Paris on July 4?

Platform comparison

Market context

Paris is locked into its second major heatwave of 2026, with temperatures set to climb sharply from Wednesday through the weekend, directly contradicting the market’s current 0% probability for any outcome above the baseline. The last 48 hours have seen Météo France escalate warnings to an orange alert for the greater Paris region, forecasting at least five consecutive days above 35°C and peaks reaching 37°C by Friday and Sunday. This immediate surge in official forecasts has shifted the collective view, with Polymarket now assigning a 43% chance to 31°C and 96% to 30°C, reflecting a rapid realisation that the “no heat” scenario is effectively dead[1].

Historically, July 4 in Paris rarely sees temperatures below 30°C during active heatwaves, and the current orange alert mirrors conditions from the record-breaking July 2003 event, where daytime highs exceeded 40°C and nights offered little relief[5]. The pattern of “tropical nights” with lows staying above 20°C is a consistent feature of these severe events, making a sub-30°C outcome highly improbable once the heat dome fully establishes itself over the city[3]. Traders should watch the daily 12:00 UTC Météo France updates for the orange alert confirmation and the specific hourly temperature breakdowns for Paris-Le Bourget, as the settlement source relies on Wunderground’s highest recorded figure for the day[3]. The next critical catalyst is the Friday forecast, which Météo France projects as the most intense day, potentially pushing the airport station near its all-time June record threshold[3].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Paris on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Prediction Today, which mirrors the Polymarket order book at 0% fees.

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 Prediction Today. 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.

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.