Highest temperature in London on August 6?

Platform comparison

Market context

The event is the **highest recorded temperature** at London City Airport on 6 August 2026, measured in degrees Celsius and mapped into a fixed range at settlement. In prediction markets, a **YES share** pays out if the stated outcome happens; a **NO share** pays out if it does not, so the price is the crowd’s live estimate of the chance that outcome will occur. With the market currently showing 0% YES, traders are effectively saying the specific temperature band tied to a YES payoff is viewed as highly unlikely at the moment.[2]

The historical lens matters because London’s August temperatures are usually far below heatwave extremes, but brief hot spells do occur. Forecast data for London in August 2026 has centred on highs in the low-to-mid 20s Celsius, while broader UK coverage this summer has already shown that the capital can spike much higher during short-lived hot episodes, including temperatures above 32°C in the latest heat spell.[1][4][14] For a banded temperature market, the key is not just whether it gets warm, but whether the day’s *single highest reading* lands inside the exact interval that determines settlement.[2]

Traders should watch the late-morning and early-afternoon forecast updates for London, since the market resolves on the highest temperature recorded before 12:00 UTC and can move quickly if the morning starts cooler or warmer than expected. The main catalysts are changes in local forecast guidance, any shift in cloud cover, sea-breeze effects, or a developing hot spell over southern England; London is often among the first places to test the upper end of UK summer temperatures when continental heat builds.[2][17] The resolution source is Wunderground’s London City Airport history page, so the final print there is what matters, not a broader London average.[2]

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

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

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.

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%.