Highest temperature in Paris on July 16?

Platform comparison

Market context

Paris is facing an intense heatwave on 16 July 2026, with forecasters warning temperatures could soar between 36°C and 39°C, potentially reaching 40°C on some afternoons. This extreme event frames the current prediction market, where the crowd-implied probability for a "YES" outcome sits at 0%, yet Polymarket data shows a 53% chance assigned to 33°C as the frontrunner, with 32°C at 30%. This divergence highlights a significant disconnect between the zero probability on one platform and the strong consensus for mid-30s temperatures on another, suggesting traders are pricing in a hot day that falls just below the 40°C historical peak Paris has only hit a few times.

Historical records indicate that while 40°C is extremely rare for the city, sustained heatwaves lasting several days are becoming more common, with Météo Horizon projecting July maximums around 25°C as a baseline that this event clearly overshoots. The current 0% implied probability appears to misalign with the 53% odds for 33°C on Polymarket, creating a clear arbitrage opportunity for those comparing cross-platform lines. Traders should monitor real-time updates from Wunderground, the official resolution source for the Paris-Le Bourget Airport Station, as forecasters believe cooler Atlantic air may arrive by the end of the week, potentially dropping temperatures below 30°C.

The primary catalyst for this contract is the daily temperature reading at Paris-Le Bourget, which will be confirmed via Wunderground’s history page for Bonneuil-en-France. Analysts note that relief is in sight as cooler air approaches, meaning the peak heat could be confined to the first half of the day before temperatures drop. With the settlement window ending at 12:00 UTC on 16 July, the market will resolve based on the highest temperature recorded for all times on that day, making the timing of the peak heat critical for accurate pricing across platforms.

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Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi vs Polymarket, which mirrors the Polymarket order book directly.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

Do I need to KYC for this market?

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