Highest temperature in London on August 14?

Platform comparison

Market context

On 14 August 2026, London City Airport will record its highest temperature for that calendar date. The market settles on the specific reading from Weather Underground's Daily Observations table at the airport station, measured in Celsius, with the crowd currently pricing all temperature ranges at zero probability—a technical artefact suggesting insufficient liquidity or settlement specification concerns rather than genuine confidence in any outcome.

August temperatures at London City Airport historically cluster between 18°C and 24°C for daily highs, with the airport's all-time August record standing at 32.1°C (set in 2022). The 2026 date falls within the typical summer season when Atlantic weather systems and continental heat drifts create variability; comparing to recent Augusts, 2023 saw highs around 20–22°C whilst 2022's exceptional heatwave pushed readings well above 30°C. The zero-probability pricing reflects either market participants' unfamiliarity with the specific Weather Underground resolution methodology or genuine uncertainty about whether the Daily Observations table will diverge from standard reporting.

Traders should monitor the UK Met Office's seasonal outlooks released in July 2026, which typically forecast temperature anomalies three to four weeks ahead. Specific triggers include any Atlantic blocking patterns (high-pressure systems stalling over the British Isles) announced in early August, which would drive continental warmth northward, and any official heat-health alerts issued by the UK Health Security Agency. The resolution hinges entirely on Weather Underground's data capture at that specific station; any technical outages or sensor recalibration during the settlement window could create disputes, making the source documentation critical for position holders.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 PolyGram. 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%.