Highest temperature in Madrid on August 17?

Platform comparison

Market context

On 17 August 2026, Madrid's highest temperature will be recorded at Adolfo Suárez Madrid-Barajas Airport and measured against discrete Celsius ranges. The market currently prices all outcomes at 0% YES across the board on Polygon, suggesting either a technical issue with the conditional token distribution or that traders have not yet engaged with this contract. Settlement hinges on Weather Underground's Daily Observations table rather than the Day High & Low summary, a distinction that matters when automated systems and manual readings diverge—a common occurrence at major airport stations where multiple sensors operate simultaneously.

Madrid's August temperatures have historically clustered between 32–38°C, with extremes reaching 40°C during heat waves. The city experienced 40.5°C on 12 August 2022 during an Iberian heat dome, and 39.6°C on 19 August 2012. These precedents establish the upper boundary of plausible outcomes; temperatures below 28°C or above 42°C would represent statistical outliers. The 0% pricing across all ranges suggests the market has not yet attracted liquidity or that participants are waiting for nearer-term weather forecasting data to become available.

Traders should monitor European summer weather patterns from late July onwards, particularly Atlantic blocking systems that drive heat northward into the Iberian Peninsula. Spain's meteorological agency (AEMET) publishes monthly outlooks in early August; any alerts for extreme heat in the Madrid region would likely shift conditional token valuations. The settlement window closes at 12:00 UTC on 17 August, meaning afternoon temperature peaks recorded after that timestamp would not be captured, creating a timing dependency that differs from markets settling on full calendar-day highs.

Methodology

We track Highest temperature in Madrid on August 17? 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

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.

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%.