Highest temperature in Paris on August 18?

Platform comparison

Market context

The contract is currently priced at 0% on Polygon, meaning traders are assigning negligible probability to any specific temperature band for Paris-Le Bourget Airport on 18 August 2026. This reflects the extreme difficulty in forecasting a precise daily maximum temperature nearly two years in advance, where even seasonal models carry substantial uncertainty. The USDC settlement mechanism locks in whichever range contains the highest temperature recorded in Weather Underground's Daily Observations table—the granular station data rather than summary figures—making resolution mechanical once the date arrives.

August in Paris typically sees maximum temperatures between 24–27°C, though heat waves have pushed readings above 30°C in recent decades. The 2022 European summer saw Paris reach 39.5°C in mid-August, whilst the 2003 heat event recorded 39.9°C. These outliers illustrate why long-range forecasting remains unreliable; seasonal patterns favour warm conditions, but the difference between a typical August day and an exceptional one depends on atmospheric circulation patterns that meteorological models cannot reliably predict beyond two weeks. Historical volatility in August maxima—ranging from 18°C in cooler years to near 40°C in extreme events—explains why the market currently reflects deep uncertainty rather than confidence in any single band.

Traders monitoring this contract should track European summer climate indices and any emerging patterns in the 2026 Atlantic Oscillation during spring and early summer. Météo-France's seasonal outlooks, published quarterly, will provide the most credible guidance as August 2026 approaches. The resolution hinges entirely on Le Bourget's recorded data; traders should verify the station's operational status and any potential instrument changes that might affect historical comparability.

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 PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 PolyGram. 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.

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%.