Highest temperature in Amsterdam on August 15?

Platform comparison

Market context

The crowd is pricing zero probability on Amsterdam recording a temperature above 40°C on 15 August 2026, despite the market's existence suggesting at least marginal plausibility. This reflects the rarity of such extremes in the Dutch capital, where August averages peak around 22–23°C and temperatures exceeding 35°C occur perhaps once or twice per summer. The 0% implied probability indicates near-universal consensus that extreme heat on that specific date is not a realistic scenario.

Historical context shows Amsterdam has recorded temperatures above 40°C only once in reliable records—reaching 40.3°C in July 2022 during an exceptional heatwave. August temperatures have never approached this threshold; the August record sits at 35.6°C (2003). The probability distribution should reflect that single-day extremes depend on precise atmospheric conditions aligning during a narrow window. The crowd's confidence in sub-40°C outcomes is grounded in genuine climatological patterns, though the 0% floor may undervalue tail-risk scenarios involving sustained continental heat advection from central Europe.

European weather forecasting agencies, including KNMI (Royal Netherlands Meteorological Institute), will publish extended-range outlooks as August 2026 approaches. Traders should monitor spring and early summer temperature trends across northern Europe, as persistent warmth in June and July could signal atmospheric patterns favouring August extremes. The settlement hinges on Weather Underground's Daily Observations table from Amsterdam Airport Schiphol, the official reference station, making data integrity rather than forecast uncertainty the primary technical consideration.

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.

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 Who Will Win 2026. 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.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.