Highest temperature in Madrid on July 21?

Platform comparison

Market context

On 21 July 2026, Madrid's highest temperature will be recorded at Adolfo Suárez Madrid-Barajas Airport, the city's primary weather station. A prediction market allows traders to buy YES or NO shares on whether that day's peak temperature falls within a specific range. Buying a YES share means you believe the temperature will land in that bracket; a NO share means you expect it to fall outside. The market settles once Wunderground publishes the official daily high for that station, resolving all positions based on the actual recorded figure.

Madrid's July temperatures are remarkably consistent. Historical data from the airport station shows that peak daily temperatures in mid-to-late July typically cluster between 33°C and 38°C, with extremes rarely exceeding 40°C or dropping below 31°C. The current crowd probability of 0% YES suggests traders are pricing in an expectation that the temperature will fall outside whatever range this particular market specifies—either unusually cool or unusually warm for the season. Comparable years show that heat waves can push readings above 40°C, though such events occur roughly once per decade in Madrid's July record.

Traders monitoring this market should track European weather forecasts from mid-July 2026 onwards, particularly any alerts from Spain's meteorological agency (AEMET) regarding high-pressure systems or heat warnings. Atmospheric patterns across the Atlantic and North African pressure zones typically determine whether Madrid experiences a typical summer day or an anomalous spike. The settlement window closes at noon UTC on 21 July, giving traders a final window to adjust positions based on morning forecasts.

Methodology

This page reviews Highest temperature in Madrid on July 21? 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 Prediction Market UK, which mirrors the Polymarket order book at 0% fees.

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.

FAQ

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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Prediction Market UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.