Highest temperature in Madrid on August 15?

Platform comparison

Market context

Madrid's highest temperature on 15 August 2026 will be recorded at Adolfo Suárez Madrid-Barajas Airport and measured against discrete temperature bands. The market currently prices a YES outcome at 2%, reflecting trader consensus that the day will not reach the upper threshold being wagered on. Settlement depends on the Daily Observations table from Weather Underground rather than summary figures, a distinction that matters when intraday peaks diverge from official highs. Traders are transacting in USDC on Polygon, with conditional tokens reflecting their conviction on this specific date roughly two years forward.

August temperatures in Madrid typically peak between 32–38°C, with extreme heat events pushing toward 40°C occurring roughly once per decade. The city recorded 40.5°C on 3 August 2012 and 40.7°C on 13 August 2021, establishing that the upper bands being priced here sit within historical precedent rather than requiring unprecedented conditions. The 2% probability suggests the market is pricing either a specific high-temperature threshold well above typical August norms or a band that historical frequency data supports as genuinely rare for mid-August.

Traders monitoring this contract should track European summer weather patterns as 2026 approaches, particularly Atlantic oscillation forecasts and any emerging climate anomalies in the preceding months. Spanish meteorological bulletins from AEMET will provide seasonal outlooks by summer 2026. The settlement window closes at midday UTC on 15 August, meaning real-time temperature readings from the airport station become the binding data point; any discrepancy between Weather Underground's summary and its Daily Observations table will resolve in favour of the latter.

Methodology

We track Highest temperature in Madrid on August 15? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Kalshi UK. 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%.