Highest temperature in Madrid on August 7?

Platform comparison

Market context

Polymarket is pricing the highest temperature in Madrid on 7 August at **0% YES** today, even though the contract settles on the temperature band containing the **single highest reading** from Weather Underground’s Daily Observations table at Adolfo Suárez Madrid-Barajas Airport, not the headline Day High & Low figure. The on-chain position is held as conditional tokens on Polygon and funded in USDC, so the market is effectively asking where the station’s observed peak will land by the settlement cut-off, rather than what the broader city forecast says. [2]

That zero price sits against a run of hot-season comparables that usually place Madrid’s August highs in the low-to-mid 30s Celsius, with weather services showing typical August daytime maxima around 32°C to 31°C and local warnings already pointing to extreme heat risk. For 7 August itself, several forecast sources cluster around the high 30s: AccuWeather flagged a yellow warning with a maximum of 37°C, while other forecasts and live reportings point to roughly 36°C to 38°C, and Reuters noted Madrid reached 40°C during Spain’s first official heatwave earlier in the summer. [6][13][9][15]

For traders, the key catalysts are the afternoon temperature peak at the airport station, any last-minute heat advisory updates, and whether the city experiences a brief late-day surge that lifts the Daily Observations maximum above the most-traded bands. The market will be resolved from Weather Underground’s historical daily record for LEMD, so the relevant check is the station’s observed maximum rather than citywide averages or forecast app summaries. [2][6][16]

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

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.

UK Frequently Asked Questions

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.