Highest temperature in Paris on August 21?

Platform comparison

Market context

The market concerns the highest temperature recorded at Paris-Le Bourget Airport on 21 August 2026, with settlement based on the Daily Observations table from Weather Underground rather than summary figures. The current crowd-implied probability of 1% for YES suggests traders expect a relatively moderate temperature that day, though the specific threshold triggering YES remains unspecified in available documentation.

Paris experiences peak summer heat in late August, with historical August averages around 25–26°C and extreme highs occasionally exceeding 35°C. The 2003 European heat wave saw Paris reach 40.3°C in early August, whilst more recent Augusts have produced highs in the low-to-mid 30s. The 1% probability reflects either a high threshold for YES or trader consensus that August 2026 will follow typical patterns rather than exceptional heat events. Comparable prediction markets on European summer temperatures typically show similar low probabilities for extreme-heat scenarios unless seasonal forecasts signal unusual atmospheric conditions.

Traders should monitor European summer weather forecasts released in June and July 2026, particularly from Météo-France and the European Centre for Medium-Range Weather Forecasts, which provide 30-day outlooks. The North Atlantic Oscillation and sea-surface temperatures in the Atlantic will influence August weather patterns across western Europe. Any significant divergence between this market's 1% probability and consensus from meteorological services or sportsbook weather derivatives would indicate mispricing, though such divergences rarely persist given the deterministic nature of temperature measurement.

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 Best Prediction Markets, 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 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'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.