Highest temperature in Paris on July 4?

Platform comparison

Market context

The underlying event is the peak temperature recorded at Paris-Le Bourget Airport on 4 July 2026, a date historically prone to summer heatwaves in the French capital. Current crowd-implied probability sits at 0% for any outcome, which contradicts the long-term climatic reality where July highs in Paris typically range from 20°C to 43°C, with an average daily high of 26°C[1][2]. Programmatic traders evaluating this tooling should note that the 0% figure likely reflects a market error or liquidity gap rather than a genuine meteorological forecast, as the 2019 record of 43°C demonstrates the clear potential for extreme heat during this month[2][3].

A trader approaching this market programmatically must monitor real-time atmospheric pressure data and the European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal models, which often signal early heatwaves weeks in advance. Recent reporting from AP News confirms France’s susceptibility to record-breaking heat, noting that an early heatwave recently gripped Europe and pushed temperatures to unprecedented levels[4]. Conditional orders should be set to trigger if the 5-day forecast for Paris exceeds 30°C, as the settlement source relies on Wunderground data for the specific station, making high-frequency data ingestion essential for accurate position sizing[2][4]. The absence of recent temperature announcements for this specific date does not negate the historical volatility, and conditional logic should account for the 15-hour daylight window that maximises solar heating potential[2].

Sources: 1 · 2 · 3 · 4 · 5

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 Fees, 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 Fees. 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 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.