Highest temperature in Madrid on August 14?

Platform comparison

Market context

Madrid's maximum temperature on 14 August 2026 will be recorded at Adolfo Suárez Madrid-Barajas Airport and resolved against the Daily Observations table on Weather Underground. The settlement window closes at midday UTC on that date, meaning the highest temperature reading from the airport station throughout the calendar day determines the outcome. Current crowd-implied probability sits at 0%, suggesting traders are pricing in a specific temperature range as most likely, though the market structure indicates multiple outcome brackets exist across the full contract set.

August temperatures in Madrid historically cluster between 32°C and 38°C, with extreme readings above 40°C occurring roughly once per decade during heat waves. The 2022 European heat wave saw Madrid reach 40.5°C on 13 August, whilst more typical August days record highs in the 34–36°C band. The 0% probability on this particular contract reflects either extreme confidence in a narrower range or sparse trading activity; comparing against historical frequency distributions and typical late-summer patterns in central Spain provides the baseline for assessing whether current odds represent genuine market consensus or illiquidity.

European weather forecasting agencies including AEMET (Spain's national meteorological service) publish 10-day outlooks in early August, with refinements arriving weekly through mid-month. The North Atlantic Oscillation and Mediterranean pressure systems drive August variability in the Iberian Peninsula; traders should monitor early-August forecasts for heat dome positioning and any Atlantic low-pressure systems that could moderate temperatures. Recent summers have shown increasing volatility, though no systematic trend has shifted the historical August median for Madrid meaningfully higher since 2015.

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

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

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.

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.

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.