Highest temperature in Paris on July 7?

Platform comparison

Market context

The underlying real-world event is an extreme heatwave gripping Paris and northern France on 7 July 2026, with forecasts predicting highs of 41°C (106°F) and overnight lows staying above 28°C (82°F)[1]. Officials have issued a red alert for dangerous heat, advising residents to avoid heavy exercise and stay indoors between noon and 6 pm while cooling centres open in libraries and gyms[1]. This is not a typical summer day; weather experts warn the heat could persist for several more days before dropping slightly after 9 July[1].

Historically, Paris recorded 42.4°C on 25 July 2019, making the current 41°C forecast plausible yet severe[8]. Recent red alerts in June 2026 saw temperatures hit 40°C in Paris, with the national thermal indicator reaching a record 29.8°C across 30 stations[3]. The current crowd-implied probability of 0% YES suggests traders doubt the temperature will exceed the highest resolution range, yet the forecasted 41°C aligns with recent extreme cases where southern France reached 38–41°C and northern areas felt intense heat[2].

Traders should monitor Meteo France’s daily updates and any storm developments later in the week that could bring relief[1]. The settlement depends on Wunderground’s recorded highest temperature for Paris-Le Bourget Airport Station, with no manual adjustment for feels-like heat[1]. On-chain mechanics use USDC on Polygon with conditional tokens, meaning the market resolves automatically once Wunderground publishes the data[1]. A recent Reuters report noted French weather agencies forecasting record highs of 40°C on Friday afternoon, reinforcing the volatility traders face[5].

Sources: 1 · 2 · 3 · 4 · 5

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 Polymarket Scam?. 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 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.