Highest temperature in Paris on August 11?

Platform comparison

Market context

On 11 August 2026, the highest temperature recorded at Paris-Le Bourget Airport will determine the settlement outcome. The market resolves using the Daily Observations table from Weather Underground rather than the Day High & Low summary section—a distinction that matters when automated feeds pull data from different endpoints. For programmatic traders, this means validating the exact source before building conditional orders; a bot configured to monitor only the summary section could trigger on stale or preliminary figures whilst the official resolution waits on granular observation records.

Paris summer temperatures typically peak between 24–28°C in mid-August, though heat waves can push readings above 30°C. The 0% crowd probability suggests the market is either miscalibrated or reflects extreme confidence in a specific temperature band. Historical August 11th data from Le Bourget shows variability: the station recorded 27.8°C on 11 August 2023 and 25.1°C in 2022. Traders should cross-reference multi-year patterns against the resolution brackets to identify which ranges carry genuine tail risk versus consensus expectations.

Catalysts include European weather pattern shifts in late July and early August, particularly Atlantic high-pressure systems or continental heat advection from the south. Météo-France publishes extended forecasts from mid-July onwards; traders using API integrations should schedule data pulls around their Thursday forecast updates. The settlement window closes at 12:00 UTC on 11 August, meaning intraday temperature movements after midnight could shift outcomes, making real-time station data feeds essential for late-market position adjustments.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

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.

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%.