Highest temperature in London on August 6?

Platform comparison

Market context

The real-world event is whether London City Airport records the day’s highest temperature on 6 August 2026, with settlement based on the Wunderground daily history page for that station. At 0% YES, the market is pricing an extreme favourite/underdog split: the consensus is effectively “no hot spike”, and the only value angle is a contrarian one that London briefly outperforms the forecast if sunshine breaks through or a warmer airmass arrives later in the day.

On the historical frame, August in London usually sits in the low 20s Celsius rather than anything exceptional, and long-run August averages are around 22°C, with typical highs in the high teens to low 20s. Current forecast material is similar: AccuWeather shows London’s August 2026 highs mostly between 67°F and 78°F, while today’s public forecast coverage points to a mild 22°C day with only sunny intervals, which supports the market’s low yes probability rather than a heat-driven surprise. The favourite remains the “ordinary August day” outcome; the underdog is a late-day warm-up that pushes the airport reading higher than the early forecast band. [1][7][3]

What traders should watch is the intraday temperature path at London City Airport rather than the city-wide headline forecast. If the morning starts cool and maritime, the afternoon ceiling may stay capped; if the sun holds and winds ease, the high can land a few degrees above expectation. Recent UK weather reporting has also shown how quickly the southeast can warm when continental air arrives, with the Met Office noting UK daily maximums are already above average this summer even if they are not at record levels, so any fresh warm spell or forecast upgrade would be the main catalyst for a move away from zero-probability pricing. [14][11]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on August 6? 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 Who Will Win. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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%.