Highest temperature in Paris on July 27?

Platform comparison

Market context

On 27 July 2026, the highest temperature recorded at Paris-Le Bourget Airport Station will fall into one of several defined ranges. The market settles on data from Wunderground's historical weather records, capturing the daily maximum temperature in degrees Celsius. Le Bourget, situated north of central Paris, typically experiences summer highs between 24–28°C in late July, though heat waves can push readings substantially higher.

Paris has recorded temperatures exceeding 40°C on multiple occasions in recent decades, most notably 42.6°C in June 2022 and 40.3°C in July 2019. However, such extremes remain uncommon for late July specifically. Historical July data from Le Bourget shows that temperatures in the 26–30°C band occur most frequently, with readings above 35°C appearing roughly once per decade. The 0% crowd probability currently assigned suggests traders expect a relatively moderate outcome, consistent with typical late-July conditions rather than an anomalous heat event.

The primary catalyst affecting this market is medium-range European weather forecasting, which becomes actionable from mid-July onwards. Météo-France and the European Centre for Medium-Range Weather Forecasts (ECMWF) typically issue reliable 10–14 day outlooks by late June. Any significant Atlantic blocking pattern or Saharan heat transport in the forecast window would shift probabilities toward higher temperature ranges. Traders should monitor these forecasts from approximately 10–14 days before settlement, as they represent the most reliable signal for anomalous conditions. Standard seasonal patterns and historical frequency distributions currently dominate the pricing.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.

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.