Highest temperature in Madrid on August 7?

Platform comparison

Market context

Madrid’s hottest reading on 7 August will be set by the maximum observed at the airport station in Weather Underground’s **Daily Observations** table, so the practical task is to watch the station feed rather than the summary high/low panel. For a programmatic workflow, that means polling the specific station’s hourly or observations endpoint, normalising timestamps to UTC, and mapping the day’s peak Celsius value into the market’s settlement bands before the window closes.

The 0% implied chance of YES is only a clean signal if the market’s highest band is still materially above Madrid’s expected range; otherwise it can reflect thin liquidity rather than a real forecast. Madrid’s August climate is hot but variable, with AccuWeather’s monthly normals around **31°C / 88°F** for the first week and historical July–August highs near **40.7°C** at central stations, showing that extreme readings are possible in peak summer even if they are not the baseline.[1][6] Time-and-date’s recent weather archive also shows how quickly Madrid can run into the mid-to-high 30s on consecutive afternoons, which is the regime traders need to model rather than single-point daily forecasts.[4]

For catalysts, the main dependency is the afternoon heating cycle and any Spain-wide heatwave warnings, since those can push station maxima materially higher than the morning forecast. The useful trigger set is therefore official AEMET heat notices, airport-station observation updates, and short-term forecast revisions from services such as the Met Office, which can be checked automatically and compared against the market’s bands throughout the day.[5] News coverage of Spain’s current summer heat and wildfire risk is also relevant insofar as it indicates whether a broader hot-air mass is affecting central Spain, but the settlement still turns on the recorded airport maximum rather than national headlines.[9][10]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Madrid on August 7? 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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Kalshi Fees. 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.

Do I need to KYC for this market?

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