Highest temperature in Paris on July 20?

Platform comparison

Market context

Paris is about to experience an intense heatwave with temperatures expected to soar between 36°C and 39°C, potentially reaching 40°C on some afternoons. This extreme event is currently unfolding in mid-July 2026, with forecasters warning the high temperatures will persist for several consecutive days before cooler Atlantic air arrives later in the week.

Historically, July is Paris’s hottest month, with average highs of 25–27°C, but canicules routinely push readings to 35–40°C, especially in mid-July. The current crowd-implied probability of 0% for the highest temperature falling into the upper ranges appears inconsistent with these active forecasts, which suggest a near-certain breach of 35°C. Programmatic traders should note that Polymarket’s frontrunner for the 20 July event is 24°C at 100%, a figure that contradicts the live heatwave data showing temperatures well above 36°C.

Key catalysts include Météo-France’s official bulletins and the Wunderground settlement source, which will record the peak temperature at Paris-Le Bourget Airport. Traders must monitor the timing of the Atlantic cooling front, as relief is forecast by the end of this week, potentially dropping temperatures below 30°C. The uncertainty lies in whether the peak occurs before or after the 20 July settlement window, with Météo-France indicating the heatwave could persist past 14 July but with considerable uncertainty on the exact end date.

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Methodology

This page reviews Highest temperature in Paris on July 20? 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 Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

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 Kalshi Fees. 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'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.

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.