Highest temperature in Paris on August 21?

Platform comparison

Market context

On 21 August 2026, the highest temperature recorded at Paris-Le Bourget Airport will fall into one of several predefined ranges. The market resolves using the Daily Observations table from Weather Underground rather than the Day High & Low summary—a distinction that matters when automated feeds pull data from different endpoints. For programmatic traders, this means validating the exact table source before settlement and accounting for potential timestamp misalignments between real-time station data and historical archives.

Paris's August temperatures have historically clustered between 24–28°C, with extremes reaching 32–35°C during heat waves. The 1% implied probability suggests the crowd expects a notably high reading—likely above 30°C or into a distinctly elevated bracket. August 2003 saw Paris peak at 38.3°C during Europe's severe heat event; more recently, August 2022 brought peaks near 35°C. These precedents frame the baseline: sustained high pressure systems and continental air masses drive the outlier scenarios the market is pricing.

Traders should monitor European weather forecasting updates from Météo-France and ECMWF model runs as August 2026 approaches. Seasonal patterns favour warm conditions, but the specific range outcomes depend on whether Atlantic low-pressure systems penetrate France or if Azores high-pressure dominates. For conditional order strategies, setting triggers on 10-day ensemble forecasts—particularly divergence between model runs—offers early signal detection. The Weather Underground data pipeline's historical reliability matters; cross-referencing against Météo-France's official station records during the settlement window will be essential for dispute resolution.

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 Polymarket Review UK, 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.

UK Frequently Asked Questions

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 Polymarket Review UK. 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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.