Highest temperature in Madrid on July 12?

Platform comparison

Market context

Madrid is currently baking under an intense summer heatwave, with temperatures soaring well above seasonal averages across central Spain. On-chain, Polymarket prices the contract for the highest temperature on 12 July 2026 at Barajas Airport with a 0% YES probability for the implied range, suggesting the crowd expects the peak to fall outside the specific bracket offered. This pricing aligns with the recent volatility seen in early July, where Barajas recorded highs of 42°C on 5–6 July, pushing the city into record-breaking territory and triggering emergency alerts across nine regions [3][8].

Historical data from the first half of 2026 shows Spain experienced its hottest start to a year since records began, with temperatures averaging 1.6°C above normal levels [10]. The market’s current 0% probability likely reflects a shift in atmospheric conditions; while early July saw sustained peaks above 40°C, the settlement window closes at midday UTC (14:00 local), capturing only the morning-to-early-afternoon peak. Traders should watch the European heatwave update schedules and AEMET station reports for Barajas, as a cooling Atlantic influence or cloud cover could suppress the daily maximum below the threshold required for a YES resolution [3][5].

The contract resolves on USDC via Polygon using conditional tokens, where a single degree determines the winner. With the settlement timestamp fixed at 12:00 UTC, the outcome hinges entirely on whether the heat pulse persists through the morning hours. Recent news confirms authorities expect heat to remain above 40°C until at least 7 July, but the trajectory for 12 July remains uncertain as the heatwave evolves [3]. Traders monitoring the Wunderground history for LEMD will find the definitive data point once the day concludes.

Sources: 1 · 2 · 3 · 4 · 5

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

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

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 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 PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.