Highest temperature in Amsterdam on August 17?

Platform comparison

Market context

Amsterdam's highest temperature on 17 August 2026 will be measured at Schiphol Airport and resolved against the Daily Observations table on Weather Underground, with settlement in USDC on the prediction market. The 0% crowd probability reflects the market's current inability to price a specific temperature range for a date nearly two years away, where atmospheric conditions remain entirely unforecast by operational meteorology.

Historical August temperatures at Schiphol show a median high of 22–23 °C, with extremes ranging from 12 °C to 32 °C across the past three decades. The 1994 European heat wave pushed Amsterdam to 30 °C on 17 August itself, whilst cooler years have settled around 18–20 °C. Current climate data from NOAA indicates a gradual warming trend in northern Europe, raising the statistical likelihood of temperatures above the long-term median, though no single August day can be reliably predicted this far in advance. The crowd's zero probability assignment suggests traders are treating this as a pure information discovery event rather than a directional climate bet.

Traders monitoring this market should track European summer weather pattern forecasts as August 2026 approaches, particularly the North Atlantic Oscillation index and jet stream positioning published by the UK Met Office. Any sustained heat dome formation across western Europe in late July or early August would sharpen probability estimates. Settlement precision depends on Weather Underground's data availability and the specific temperature bins offered; discrepancies between the Daily Observations table and summary highs have historically resolved in favour of the former, per the market's specification.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

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%.