Highest temperature in Madrid on August 14?

Platform comparison

Market context

Madrid's August weather remains firmly in summer pattern territory, with the city's typical heat persisting through mid-month. The 0% crowd probability reflects the market's current state rather than any recent shift in meteorological conditions; no significant weather system has emerged in the past 48 hours to alter baseline expectations for 14 August 2026.

Historical August temperatures at Adolfo Suárez Madrid-Barajas Airport show consistent extremes. Over the past two decades, daily highs in mid-August have regularly exceeded 35°C, with several years recording peaks above 38°C. The airport station's readings—which this market uses exclusively from the Daily Observations table—tend to run slightly cooler than central Madrid due to its location on the city's periphery, though still well within the hot range. August 2023 saw a peak of 40.5°C on the 15th, whilst 2022 recorded 39.2°C on the 13th, establishing the pattern traders should reference when assessing probability ranges.

The primary catalyst for any meaningful deviation would be an unexpected Atlantic weather system pushing northward, though such intrusions in mid-August remain uncommon. Traders should monitor European weather forecasts from mid-July onwards, particularly any signals from ECMWF or national meteorological services regarding upper-level patterns. The settlement window closes at 12:00 UTC on 14 August, meaning the market resolves based on observations recorded through that point, not the full calendar day.

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.

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 Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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%.