Highest temperature in London on August 10?

Platform comparison

Market context

The real-world event is whether London City Airport’s recorded high temperature on 10 August falls into a specific Celsius band, using Weather Underground’s Daily Observations table as the settlement source rather than the summary high/low display. That matters because the market is not about the forecast headline figure, but the actual station reading that survives until the first datapoint for 11 August is published, so late revisions can still change the outcome if they appear before that cut-off.[1]

A 0% implied probability for YES is a strong signal of either a market mispricing or an outcome that traders currently see as extremely unlikely, but London August history argues against treating low probabilities as impossible. London has produced repeated warm spells in early and mid-August, and comparable UK records show 10 August can fall on either side of heatwave conditions, with 2003 still the benchmark date for extreme August heat in Britain and Heathrow/Kew posting very high readings that day.[2][4][10] For a London airport station specifically, warm days can still finish well below the national record, so the relevant comparison is the airport’s own August range rather than the UK headline extreme.[8][11]

For accessibility, the main regulatory angle is that prediction markets can sit in a grey zone across jurisdictions: German GlüStV rules may treat betting-like products as gambling where local access and promotion are restricted, while the US CFTC can assert reach if a market is viewed as a derivatives-style event contract. “No-KYC up to $1,500” usually means smaller deposits, trades, or withdrawals can be completed without full identity verification, which lowers friction for casual access but does not remove geo-blocking, sanctions screening, or any venue-specific eligibility limits. Traders should also watch the station’s observation cadence and any local weather developments, since a late warm surge, sea-breeze shift, or timing issue around the final published reading can move the closing band even after the day’s apparent peak has passed.[1][3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This overview of Highest temperature in London on August 10? reviews the four comparable platforms from a regulatory perspective: which is accessible in your jurisdiction, where KYC kicks in, how the platform is classified by your country of residence. Live probability is the Polymarket mid; comparison columns show regulatory status, KYC thresholds and settlement options for each platform.

Resolution & payout

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UK Frequently Asked Questions

How are winnings taxed?

Tax treatment varies by jurisdiction. In most countries, prediction market gains are treated as ordinary income or capital gains. We cannot provide tax advice — consult a tax professional for your specific situation.

Is Polymarket regulated by the UKGC?

No. Polymarket is not licensed by the UK Gambling Commission (UKGC). It is a decentralised prediction market operated under US regulation. UK traders can use it but do not benefit from UKGC dispute resolution or player protection requirements.

What are the HMRC tax rules on Polymarket profits for UK traders?

Polymarket profits are treated as cryptocurrency disposal events by HMRC. Each USDC settlement is a taxable event subject to Capital Gains Tax (CGT). For 2026/27, the CGT rate is 18% (basic rate) or 24% (higher rate). The annual CGT exemption is £3,000. Report via HMRC Self Assessment if your total crypto gains exceed £3,000 or proceeds exceed £50,000.

Does Polymarket KYC apply to UK users?

Yes. Polymarket requires KYC (Know Your Customer) verification for all users, including UK residents. You must provide a government-issued photo ID and a selfie. The process typically takes 5–10 minutes via their ID verification provider.

What is the legal difference between Polymarket and Betfair Exchange for UK traders?

Betfair Exchange is UKGC-licensed, meaning UK consumer protections apply and winnings are typically tax-free. Polymarket is not UKGC-licensed — it operates under decentralised blockchain rules. Profits from Polymarket are subject to HMRC CGT as crypto disposals. Choose based on your regulatory preference and tax situation.