Highest temperature in Madrid on July 22?

Platform comparison

Market context

Madrid’s airport weather reading is pointing to a very hot afternoon, and the market is currently pricing the outcome conservatively against the forecast. Polymarket shows **39°C** as the clear frontrunner at **77%**, with **40°C** next at **21%**, while one local forecast published on 22 July put Madrid’s maximum at **39°C** and described **0%** rain probability.[1][2]

That split matters because the contract settles on the *highest recorded temperature* at Adolfo Suárez Madrid-Barajas Airport, not the citywide headline forecast, so a one-degree overshoot can change the outcome. In recent comparable heatwave coverage, Madrid has repeatedly been forecast in the high-30s to low-40s Celsius, which is consistent with why the crowd is concentrated around 39–40°C rather than lower bands.[3][4] The current **0% YES** crowd-implied probability indicates either a contract-price anomaly, a stale book, or a market with no meaningful liquidity, and it sits well below the forecast tone from Spanish media and the broader heatwave reporting.[1][2][3]

Traders should watch the late-afternoon evolution at Madrid-Barajas, because the contract’s outcome can still move on the basis of the day’s official maximum at the airport station before the settlement window closes. The key dependencies are the timing of the warmest part of the day, any convective cloud build-up, and whether official airport observations edge above the city forecast; local reporting on 22 July already signalled hot, dry conditions, which leaves limited room for a cooler-than-expected reading but still a real chance of a 40°C print if the airport peaks late.[2]

Sources: 1 · 2 · 3 · 4

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.

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 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.