Highest temperature in London on August 13?

Platform comparison

Market context

London's weather on 13 August 2026 remains highly uncertain, with the settlement window still eighteen months away. Current crowd pricing reflects this distance—the 0% implied probability suggests traders are either heavily discounting near-term forecasting reliability or treating this as a placeholder market pending closer-range meteorological data. August in London typically sees daily highs between 20–24°C, though heat waves can push readings into the high 20s or low 30s. The specific resolution mechanism—using Weather Underground's Daily Observations table from London City Airport rather than summary figures—introduces a technical precision requirement that traders should note, as airport station readings can differ from broader city measurements.

Historical August temperatures in London show considerable year-to-year variation. The 2022 heat wave drove readings above 35°C across parts of the UK, whilst more typical recent Augusts have peaked in the 22–26°C range. The Met Office's seasonal outlooks, typically issued 30 days before the target period, will provide the first substantive catalyst for market movement. Traders should monitor spring and early summer 2026 climate patterns—particularly Atlantic pressure systems and any emerging signals of persistent high-pressure systems over northern Europe—as these will shape August conditions. The UK's Climate Projections data, updated periodically, may also influence longer-range positioning as the date approaches.

Methodology

We track Highest temperature in London on August 13? 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 Prediction Today. 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%.