Highest temperature in Madrid on July 31?

Platform comparison

Market context

Madrid’s high at Barajas on 31 July is the event to watch, and the market is pricing a **0% YES** chance, so the consensus is firmly that the day’s maximum will not land in the relevant temperature band. That makes YES the obvious **underdog**, with any value resting only in a late heat spike large enough to break expectations rather than in an average summer outcome.

The historical frame still leans warm enough to explain why the market is set where it is. July in Madrid is typically hot, with average highs around **33°C**, while current monthly outlooks show late-July daytime peaks in the mid-30s to mid-90s Fahrenheit, consistent with a city that regularly reaches the upper 30s in summer. Recent coverage for 31 July 2026 points to a forecast maximum of **38°C** and **0%** rain, which supports a high-temperature regime rather than a cool disruption.[1][4][17] The contrarian angle is that airport stations can differ from city-centre readings, so a settled forecast near the high 30s still leaves room for a slightly lower realised airport maximum if cloud, wind, or timing trims the peak.

Traders should watch the midday and afternoon forecast updates, because the settlement window ends at **12:00 UTC**, before the warmest part of the local afternoon, so the market is effectively locked to whatever the airport is already trending towards by late morning. The key dependency is the actual Wunderground Barajas history page, since that is the resolution source, not a generic Madrid forecast. In handicapper terms, the favourite is the hot-day outcome, but the market’s 0% print suggests the consensus already assumes the wrong temperature band, which is where the only meaningful value on the board is likely to sit.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Madrid on July 31? 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

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

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 Who Will Win 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.