Highest temperature in Madrid on August 14?

Platform comparison

Market context

On 14 August 2026, Madrid's highest temperature will be measured at Adolfo Suárez Madrid-Barajas Airport Station and recorded in Weather Underground's Daily Observations table. The market currently prices all temperature ranges at 0% YES on Polygon, meaning traders are not allocating conditional token value to any outcome—an unusual state suggesting either insufficient liquidity or a technical settlement concern rather than genuine uncertainty about whether temperatures will occur. Resolution hinges on the specific data point from Wunderground's Daily Observations section, not the Day High & Low summary, a distinction that matters when automated weather feeds occasionally diverge.

August temperatures in Madrid historically cluster between 32–38°C, with the city's all-time August high of 40.5°C recorded in 2003. Recent summers have seen consistent peaks in the 35–37°C range, though the 2022 heatwave pushed readings to 39°C. The current 0% pricing across all ranges reflects either market formation lag or traders awaiting confirmation that Wunderground's historical data for this specific station and date will be accessible at settlement.

Traders should monitor Spanish meteorological forecasts from AEMET (Agencia Estatal de Meteorología) in the weeks preceding mid-August 2026, particularly any heat advisories or anomalous pressure systems. The settlement window closes at 12:00 UTC on 14 August, meaning intraday temperature movements matter; afternoon peaks typically exceed morning readings by 5–8°C in Madrid. Any disruption to Wunderground's data collection or station operations would trigger resolution disputes.

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

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

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 Polymarket Scam?. 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.

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%.