Highest temperature in Paris on July 4?

Platform comparison

Market context

The real-world event hinges on whether Paris-Le Bourget will hit a specific heat threshold on 4 July 2026, with the crowd currently assigning a 0% chance to the "YES" outcome for the highest temperature range. This near-zero implied probability suggests the consensus believes extreme heat is unlikely, yet historical data frames a different narrative. July in Paris is a month of heat-wave potential, where average highs sit at 26°C but the range of daily peaks stretches from 20°C to a searing 43°C, the latter recorded in 2019[2]. With the national record for France hitting 44.3°C in Landes recently during a brutal European heatwave, the value spot for a contrarian trader lies in betting against the 0% line, as the market may be underpricing the volatility of early summer weather patterns[4].

Traders must monitor the arrival of early-season heat advisories and the Met Office’s forecasts for western Europe, as these schedules often dictate temperature spikes before the settlement window closes. Recent reports confirm France has set new records for its hottest day ever, with a peak of 44.3°C measured in the southwest, indicating that severe heatwaves are a recurring catalyst rather than an anomaly[4]. The dependency here is the timing of the heatwave; if the thermal marker for France continues to climb as it did in June, the Paris-Le Bourget station could easily breach the 31°C threshold that the Polymarket frontrunner currently prices at 43%[1]. Ignoring these recent heat records leaves the consensus exposed to a significant contrarian angle where the 0% probability is a mispricing of the current climate trajectory.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Paris on July 4? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Who Will Win 2026. 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.

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 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 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.