Highest temperature in London on August 14?

Platform comparison

Market context

On 14 August 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges, measured in degrees Celsius via Weather Underground's Daily Observations table. The market currently prices all YES outcomes at 0%, meaning traders are pricing in either extreme confidence in a specific temperature band or technical liquidity constraints on Polygon. Settlement hinges on the precise reading from the designated weather station, not summary figures, creating a narrow resolution criterion that eliminates ambiguity but requires careful attention to data source hierarchy.

London's August temperatures have historically clustered between 20–28°C, with extremes rare but documented. The summer of 2022 saw the UK record 40.3°C nationally, though London City Airport recorded 37.1°C that day. August typically ranks among the warmest months, yet the capital's maritime influence and urban heat island effects create variability year to year. Comparing this market's 0% probability against climatological norms suggests either the crowd has priced in a specific narrow band as near-certain, or the conditional token structure on Polygon has created a liquidity desert across all ranges.

Traders should monitor the Met Office's seasonal outlook for summer 2026, expected in June, which will signal whether anomalous heat or cooler-than-average conditions are forecast. Real-time tracking of European weather patterns in early August will matter more; Atlantic pressure systems and jet stream positioning typically determine whether high-pressure systems deliver heat or Atlantic lows bring cooler air. Any major heatwave warnings issued in the fortnight before settlement would shift market pricing materially, as would confirmation of normal summer conditions.

Methodology

We track Highest temperature in London on August 14? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Polymarket Scam?. 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%.