Highest temperature in Paris on July 17?

Platform comparison

Market context

Paris-Le Bourget Airport is set to record its peak temperature for 17 July 2026, with the prediction market currently pricing a 0% chance that the outcome will fall into the highest available range. This near-zero implied probability reflects a collective consensus that extreme heat is unlikely, aligning with the market’s frontrunner outcome of 26°C, which commands a 92% share of trading volume on Polymarket [1]. The next closest outcome, 27°C, holds only 7%, suggesting traders view a significant spike above 26°C as improbable given current atmospheric conditions.

Historical July highs in Paris typically cluster between 24°C and 28°C, with temperatures exceeding 30°C occurring in only a minority of years, often tied to specific heatwave events like those in 2019 or 2022. The current 0% probability for the highest range mirrors these patterns, indicating the market expects conditions to remain within the moderate band rather than breach extreme thresholds. This framing helps traders contextualise the odds as consistent with long-term climatic norms rather than an outlier signal.

Traders should monitor real-time weather updates from Wunderground, the designated resolution source, and watch for any sudden shifts in European heat forecasts from the Met Office or Météo-France, which could alter implied probabilities before the settlement window closes on 17 July 2026 at 12:00 UTC. While no specific announcements are pending, rapid changes in regional pressure systems or cloud cover could act as catalysts for odds movement, particularly if forecasts diverge from the current 26°C consensus [1].

Sources: 1

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 vs Polymarket. 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.

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 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.