Highest temperature in Madrid on July 22?

Platform comparison

Market context

The key real-world variable is the **highest temperature recorded at Madrid-Barajas airport on 22 July**, and the market is already pricing a very hot outcome: Polymarket has **39°C** as the front-runner at **77%**, with **40°C** next at **21%**.[1] That leaves only a small residual chance on other bins, so the contract is effectively trading as a call on whether Madrid peaks in the high-30s or pushes into 40°C territory.[1]

Historical framing supports that split. A local forecast published on 22 July put Madrid’s maximum at **39°C** with **0% rain** and very little cloud, which is consistent with a day that can still drift up by a degree if the airport station runs hot in the afternoon.[2] Broader heatwave coverage for central Spain has also pointed to Madrid repeatedly sitting in the **37–41°C** band during July 2026, which makes both 39°C and 40°C credible outcomes rather than a wide-open contest.[3] The 0% YES crowd price is therefore hard to reconcile with the public forecast picture, unless the market is using a different temperature bucket than the headline expectation.

For traders, the main catalysts are not policy or scheduling shocks but the *timing* of the day’s peak and any late-morning forecast updates. Because the contract settles on the airport station’s **highest daily reading** before the window closes, a late-afternoon surge matters more than the early-day print, and any revision in Madrid’s official forecast, cloud cover, or heat-advisory wording can move the closer bins. Cross-platform comparison matters here: prediction-market pricing is already concentrated around 39°C/40°C, while the available public forecast consensus points to a maximum around 39°C.[1][2]

Sources: 1 · 2 · 3

Methodology

We track Highest temperature in Madrid on July 22? 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

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.

Do I need to KYC for this market?

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