Highest temperature in Paris on July 20?

Platform comparison

Market context

Paris-Le Bourget recorded a maximum of 25°C on Monday, 20 July 2026, confirming a sharp break from the intense heatwave that peaked at 41°C in early July. The market’s 0% probability for any outcome above 24°C reflects this immediate cooling, with forecasts for the week of 20–26 July settling at normal summer levels between 25°C and 31°C and no extreme heat expected [2].

Historical context supports this low-probability stance: while July is Paris’s hottest month with average highs of 25–27°C, canicules typically push temperatures to 35–40°C only in mid-July, not late July [3]. The third heatwave of 2026, which began 6 July and reached 40°C in the south, is forecast to end before 20 July, with cooler Atlantic air arriving by the weekend [2][13]. Long-term averages for daytime maximums in Paris during July are 24°C, aligning with the market’s frontrunner outcome [6].

Traders should monitor Meteo-France’s daily heat alerts and the timing of the Atlantic cool front, which forecasters expect to drop temperatures below 30°C by the end of the week [2][13]. The Wunderground resolution source will record the highest temperature at Paris-Le Bourget for all times on 20 July, so any late-morning or afternoon spike above 25°C would invalidate the current 100% probability assigned to 24°C [5]. No new heat alerts are currently active for Île-de-France as of 20 July, reinforcing the expectation of breathable conditions [2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Paris on July 20? 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

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

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.

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.