Highest temperature in Paris on July 3?

Platform comparison

Market context

The real-world event at the heart of this market is the highest temperature recorded on 3 July 2026 at Paris-Le Bourget Airport, measured in degrees Celsius. In prediction markets, a YES share pays out if the temperature falls within a specific range you select, while a NO share pays out if it does not. This particular market currently shows a 0% crowd-implied probability for the lowest range, suggesting traders believe the heat will be significant.

Historical context frames this low probability: Paris has endured multiple intense heatwaves in recent years, with temperatures in the Paris region recently forecast to reach between 36°C and 38°C, and possibly up to 40°C in the south and west [4]. The 2026 European heatwaves have already set record highs, including an unofficial reading of 50°C in parts of Europe [8], and France recorded its hottest day ever with a peak of 44.3°C in Landes [6]. Given that current weather alerts for July 3–4 predict a powerful heatwave pushing temperatures sharply higher across northern France, with afternoon highs expected near 36°C to 37°C [2], the market’s dismissal of the lowest range aligns with these severe conditions.

Traders should monitor official meteorological updates from Meteo France, which has issued red heat-wave alerts for 54 departments as high temperatures persist around the clock [5]. The catalyst is the confirmed third heatwave of the year, expected to build from this weekend, with temperatures climbing again on Friday [4]. While this new heatwave may be less intense than the historic June event, the dependency on dry weather and almost no rain expected [2] means cooling relief will be limited, reinforcing the likelihood of high temperatures.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Paris on July 3? 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

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.

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.