Highest temperature in Paris on August 18?

Platform comparison

Market context

On 18 August 2026, the highest temperature recorded at Paris-Le Bourget Airport will fall into one of several defined ranges. Polymarket currently prices this contract at 0% YES, meaning traders are assigning negligible probability to whichever specific temperature band this market tracks. The settlement hinges on Weather Underground's Daily Observations table rather than summary figures, a distinction that matters when automated systems and manual readings diverge—a common source of disputes in weather markets.

Paris experiences peak summer heat in mid-August, with historical August highs typically ranging between 24–28°C at Le Bourget. The 0% probability suggests the market is pricing an outcome well outside normal seasonal bounds, or reflects thin liquidity and low trading volume on a niche weather contract. August 2025 saw Paris reach 29°C on the 18th; the preceding decade shows considerable year-to-year variation, with some August 18ths reaching only 20°C and others exceeding 30°C. This volatility undercuts any assumption of predictability two years ahead.

Traders monitoring this contract should track seasonal forecasts from Météo-France as summer 2026 approaches, particularly any signals of heat dome formation or Atlantic weather pattern shifts in late July. The contract's settlement depends entirely on Le Bourget's recorded data; any station maintenance or sensor recalibration could affect readings. With settlement occurring at 12:00 UTC on the day itself, real-time temperature tracking becomes relevant only in the final hours, leaving most of the contract's lifespan dependent on longer-range climate patterns and historical precedent rather than actionable near-term signals.

Methodology

This page reviews Highest temperature in Paris on August 18? 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 Polymarket Scam?, 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.

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

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.

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%.