Highest temperature in Madrid on July 25?

Platform comparison

Market context

Madrid's weather on 25 July 2026 will be measured at Adolfo Suárez Madrid-Barajas Airport, with the settlement hinging on the single highest temperature recorded that day in Celsius. The 4% implied probability suggests traders expect temperatures to remain within a moderate range, though the specific threshold triggering a YES resolution remains unspecified in the market structure.

Historical July temperatures at Madrid-Barajas show the airport regularly records highs between 32–36°C during summer, with extremes occasionally reaching 38–40°C during heat waves. The station's 30-year average for late July sits around 34°C. Spain experienced notable heat events in July 2022 and July 2023, when several regions exceeded 40°C, though Madrid-Barajas itself typically records slightly lower peaks than inland stations due to its elevation and airport microclimate. The current 4% probability suggests the market has set a threshold well above the historical median—likely 38°C or higher—making the YES outcome contingent on an above-average heat episode.

Traders should monitor European weather forecasting models from mid-July onwards, particularly ECMWF and GFS outputs tracking high-pressure systems over the Iberian Peninsula. Spain's meteorological agency (AEMET) typically issues heat alerts 5–10 days ahead of significant warming events. Recent patterns show July 2024 and 2025 data will provide the most relevant seasonal comparisons; any Atlantic blocking patterns developing in early July could signal sustained heat building into the settlement date. The airport station's specific microclimate—influenced by tarmac and urban heat—means readings may diverge from city-centre forecasts, a factor worth cross-referencing against Wunderground's historical records.

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

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.

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 Best Prediction Markets 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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.