Pronóstico: Highest temperature in Madrid on June 29?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at Madrid-Barajas Airport on 29 June 2026, a date that historically sits near the peak of Madrid’s summer heat. Current crowd-implied probability for the “YES” outcome is 0%, suggesting traders believe the temperature will fall outside the specified range, despite June 29 being the warmest average day of the month, reaching 31.8°C historically [6].

Historical data frames this probability with caution: in 2019, Madrid hit 40.7°C on 28 June, just one day prior, while June 22, 2026, already recorded 38.3°C in this year’s heatwave [7][9]. This year’s June has seen temperatures exceed 110°F (43°C) in parts of Spain, with Madrid experiencing its warmest night on record, where temperatures did not drop below 26.2°C [3][5]. Such extremes make a 0% probability for the range appear overly dismissive of the volatility already observed.

Traders should monitor official heatwave announcements from Spain’s meteorological agency (AEMET) and daily Wunderground updates for Barajas Airport, as settlement relies on their highest recorded temperature [source]. Recent reports from The Washington Post confirm that hundreds may have died from this record heat, underscoring the severity of the current conditions [3]. On-chain mechanics on Polymarket use USDC on Polygon, with conditional tokens determining payout; the contract’s pricing today reflects market sentiment more than climatic certainty, and any sudden forecast shifts could rapidly alter the 0% valuation.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Pronóstico: Highest temperature in Madrid on June 29? 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.

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 Polymarket Qué Es. 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.

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.

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.