Highest temperature in Paris on June 23?

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Market context

Paris-Le Bourget Airport will record its peak temperature for 23 June 2026, a single data point that determines the outcome of a weather prediction contract. While the current crowd-implied probability for a "YES" outcome sits at 0%, this figure diverges sharply from cross-platform odds. Polymarket assigns an 85% chance to the 36°C range, with 38°C or higher holding a 24% probability, suggesting a significant mispricing between the two venues where traders are betting on a hot day rather than a cool one[1].

Historical June weather in Paris typically sees daily highs rising from 69°F to 74°F, rarely exceeding 84°F, yet recent records show the capital has already broken its June temperature ceiling with 38.4°C recorded just last Monday[2][3]. Extreme heat events are not unprecedented in France, with July 2019 reaching 42.4°C in Paris and the national record hitting 45.9°C in southern France, framing the current 0% probability as an outlier against a backdrop of escalating summer temperatures[4][6].

Traders should monitor the ongoing heatwave narrative and any official meteorological updates from Euronews, which reported 18 fatalities linked to the current historically hot conditions across France[3]. The primary catalyst remains the persistence of this high-pressure system, which could push temperatures well above the seasonal average, making the 0% implied probability highly vulnerable to a rapid correction as the settlement window approaches.

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). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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

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 it cost to trade on Best Prediction Markets?

Zero. Best Prediction Markets routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.

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.