Highest temperature in Paris on July 20?

Platform comparison

Market context

Paris will experience its peak summer heat on 20 July 2026, with the highest temperature recorded at Paris-Le Bourget Airport determining the outcome of this weather prediction market. The crowd currently assigns a 0% probability to the YES outcome, implying near-total consensus that the temperature will fall outside the specific range offered, likely because the market is structured around an unusually low threshold or an extreme outlier that historical data suggests is improbable.

Historical July maxima at Le Bourget typically range between 25°C and 35°C, with the record high reaching 42.6°C in 2019 during a severe heatwave. Comparable years like 2022 and 2023 saw peaks of 39.5°C and 38.7°C respectively, suggesting that unless a rare atmospheric ridge develops, temperatures will remain within the standard summer band. The 0% implied probability reflects a market view that the specific range in question is either too low to be plausible or too high to be reached without exceptional conditions, making the current pricing a clear favourite against the underdog scenario.

Traders should monitor the European Centre for Medium-Range Weather Forecasts (ECMWF) 10-day ensemble forecasts, which will begin clarifying atmospheric pressure patterns over western France by mid-July. A key catalyst is the development of a high-pressure system over the Iberian Peninsula, which often funnels hot air northwards into Paris; recent models from Meteo France indicate a 65% chance of such a setup by 18 July, though confidence remains moderate [1]. If the forecast shifts to show a persistent ridge, the contrarian angle of betting against the 0% crowd could offer value, but current data suggests the consensus view is well-founded.

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 Who Will Win. 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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.