Highest temperature in Paris on August 18?

Platform comparison

Market context

Paris will experience some temperature on 18 August 2026, and this market captures the highest reading recorded at Le Bourget Airport that day. The resolution hinges on a specific data source—Weather Underground's Daily Observations table rather than the summary high-low figures—which matters because automated feeds and manual station logs sometimes diverge. For programmatic traders, this distinction means building a scraper that targets the correct table structure on Wunderground rather than relying on API endpoints that might pull from the summary section.

August temperatures at Le Bourget typically range between 20–28°C, with extremes occasionally reaching 30°C during heat waves. Historical August data from 2015 (when Paris recorded 37°C during a European heat event) and 2022 (39°C in parts of France) show that whilst exceptional heat is possible, it remains statistically rare. The current 0% crowd probability suggests traders are pricing in a baseline expectation rather than accounting for tail-risk heat scenarios. Comparable markets on European summer temperatures have shown that crowd estimates tend to underweight the frequency of +32°C outcomes when atmospheric blocking patterns develop.

Traders monitoring this market should track European weather model consensus from mid-August, particularly the GFS and ECMWF ensembles which typically show skill 10–14 days ahead. Jet stream positioning and high-pressure system development over continental Europe in mid-August will be the primary catalysts. The settlement window closes at noon UTC on 18 August, giving traders roughly a 12-hour window after the calendar day begins to adjust positions based on morning forecasts and early station readings.

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 Bot 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

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.

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%.