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 temperature outcomes at 0% probability on Polygon, suggesting either a technical issue with the contract's conditional token structure or that traders are awaiting clearer resolution criteria before committing USDC capital. This disconnect between market pricing and the certainty of an eventual temperature reading warrants scrutiny of how the settlement mechanism will function once the date arrives.

London's August temperatures have historically clustered between 20–26°C, with extremes rarely exceeding 30°C in the capital proper. The Met Office records show that August 2022 saw highs of 26–27°C on most days, whilst the heatwave of July 2022 pushed readings above 40°C—an outlier driven by exceptional atmospheric conditions. For City Airport specifically, which sits on the Thames estuary with moderating maritime influence, readings tend 1–2°C cooler than central London. Examining the Daily Observations table methodology is critical: this granular dataset captures sub-hourly readings rather than the rounded Day High & Low summary, potentially creating resolution disputes if the two sources diverge by fractions of a degree.

Traders should monitor the UK Met Office's long-range forecasts as summer 2026 approaches, particularly any signals of high-pressure systems or Atlantic blocking patterns that could drive temperatures upward. The contract's reliance on a single weather station and specific data table means that any Weather Underground platform changes or data corrections post-settlement could affect final resolution. Current zero pricing likely reflects uncertainty about whether the market's technical infrastructure will execute cleanly rather than doubt about whether a temperature will be recorded.

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi UK, which mirrors the Polymarket order book directly.

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

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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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%.