Highest temperature in Madrid on August 9?

Platform comparison

Market context

Polymarket is pricing the **37°C** band at **100%**, with every other outcome at **0%**, so the contract is effectively behaving like a settled carry trade in **USDC** on **Polygon** rather than a live weather punt. Because shares are conditional tokens that redeem for $1 if the correct range wins, the practical question for traders is whether the Weather Underground **Daily Observations** table for Adolfo Suárez Madrid-Barajas Airport will log a peak that stays inside that band before the settlement cut-off.

That reading fits the recent backdrop. AccuWeather’s Madrid forecast for 9 August showed about **97°F/36°C** with a very hot, sunny day, while its warning page flagged a **maximum temperature of 38°C** for the metropolitan area on 9 August.[10][4] Nearby historical context also points to a hot early-August pattern: Weather and Climate reported a **37.8°C** maximum on 7 August, and Reuters described Spain’s first official heatwave of 2026 earlier in the summer, underscoring how quickly Iberian temperatures can press into the upper 30s.[7][15]

For a Polymarket user, the key catalysts are the station obs, not broader Madrid forecasts. The market resolves from the airport station’s **Daily Observations** table, and Polymarket says revisions within the market window count until the first datapoint for the following date appears, so late adjustments in Weather Underground’s archive can still matter.[3] Traders should also watch whether the airport reports an afternoon spike above 37°C or 38°C, since that would move the payout from the currently dominant 37°C band into a higher range; by contrast, a reading below 37°C would make the 100% pricing vulnerable despite the current crowd consensus.[3]

Sources: 1 · 2 · 3 · 4 · 5

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

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 PolyGram. 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.

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.

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.