Highest temperature in Paris on July 4?

Platform comparison

Market context

On 4 July 2026, Paris-Le Bourget will record its daily peak temperature, a single real-world metric that determines whether the market resolves to 30°C or any other value. Historical data frames this 0% crowd-implied probability as an outlier: Paris July highs typically range from 20°C to 43°C, with an average daily high of 26°C and a record of 42.6°C set in 2019[2][9]. While 30°C sits comfortably within the normal summer band, the current market pricing suggests traders believe a specific exact match is statistically improbable, diverging sharply from the 44% implied probability seen on competing platforms like Lines.com for the same exact 30°C outcome[4].

Traders must monitor the Met Office’s heat-wave forecasts and local temperature advisories, as southern England and southeast Wales are already experiencing peaks near 35°C, with London potentially reaching 39°C by mid-week[5]. The resolution hinges on Wunderground’s daily high for Paris-Le Bourget, which will be influenced by the intensity of the current continental heat wave that recently forced the Louvre and Eiffel Tower to close early due to record-breaking conditions[5][6]. With continental France experiencing broken maximum temperature records in June and July 2022, the dependency on whether this specific heat wave extends into Paris on 4 July remains the critical catalyst for price movement[7].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Paris on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Best Prediction Markets, which mirrors the Polymarket order book at 0% fees.

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 Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.

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.