Highest temperature in Amsterdam on August 17?

Platform comparison

Market context

The crowd is pricing zero probability that Amsterdam's highest temperature on 17 August 2026 will fall into any specific range, suggesting either extreme uncertainty about which bracket will contain the day's peak or a technical issue with how the market has been framed. The settlement hinges on the Daily Observations table at Amsterdam Airport Schiphol Station, which records sub-daily readings and may differ materially from the Day High & Low summary figure—a distinction that matters for edge-hunting traders familiar with how weather stations report data.

Historical August temperatures in Amsterdam cluster between 17–24°C as daily highs, with occasional excursions into the mid-20s during heat waves. The 1990–2020 average high for mid-August sits around 21°C. Extreme outliers—days exceeding 30°C—occur roughly once per decade in the region. The current 0% implied probability across all ranges suggests the market may be awaiting explicit range definitions or reflects genuine disagreement about whether the question is answerable given the resolution source specification.

Traders should monitor European weather forecasts from mid-August 2025 onwards, particularly whether Atlantic low-pressure systems or continental high-pressure ridges dominate the forecast window. The Dutch Royal Meteorological Institute (KNMI) publishes seasonal outlooks that can signal whether conditions favour above or below-normal temperatures. Any major heat wave event across northern Europe in the weeks preceding 17 August would shift expectations materially, as would persistent cool, wet patterns typical of Dutch summer weather.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Who Will Win. 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%.