Highest temperature in London on August 11?

Platform comparison

Market context

On 11 August 2026, the highest temperature recorded at London City Airport will settle this market. Resolution hinges on the Daily Observations table from Weather Underground rather than summary figures, with settlement in USDC against the specific temperature range that captures the peak reading in degrees Celsius. The 0% crowd probability suggests traders are pricing near-zero conviction in any single outcome band, typical for weather markets where uncertainty remains high until the settlement window closes at 12:00 UTC on the day itself.

August temperatures at London City Airport historically cluster between 20–24°C on average, though extremes have ranged from 16°C to 32°C across the past two decades. The 2022 heatwave pushed readings above 30°C, whilst cooler Augusts have seen highs barely exceed 18°C. Current flat probability distribution reflects genuine meteorological uncertainty; no single temperature band commands meaningful edge without access to reliable seasonal forecasts or real-time atmospheric data closer to the settlement date.

Traders should monitor UK Met Office outlooks and European weather model consensus (ECMWF, GFS) from late July onwards, as these typically converge on August conditions with useful skill. Any Atlantic blocking pattern or heat dome positioning will shift probabilities materially. Funding rates on weather-derivative platforms and spot volatility in weather-linked crypto indices remain subdued; whale flows into temperature-range contracts have been minimal, suggesting institutional positioning remains light ahead of the 2026 summer season.

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

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Can I use Bitcoin directly?

No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.

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%.