Highest temperature in London on August 10?

Platform comparison

Market context

London’s highest temperature will be set by the warmest reading logged at London City Airport on 10 August, and the market settles off the **Daily Observations** table rather than any headline high/low summary. With the crowd pricing a **0%** YES probability, the implied view is that the eventual value will land outside the market’s target range, so a power-user would treat this as a data-delivery problem as much as a weather call: watch the station feed, not the banner forecast, and only update once the relevant observation is published in the source table.

For context, London’s August temperature distribution is usually modest compared with UK heat records, but the city can still spike into the high 20s or low 30s in a warm plume. Recent market snapshots have already shown expectations clustering around the mid-to-high 20s for this date, with one Polymarket listing the leading outcomes at **26°C** and **27°C** and citing model guidance for a peak near **27°C** after a hotter 9 August. That matters for interpretation because a 0% implied chance is only defensible if traders believe the observed value will miss every listed band, which is unusual unless the market is stale, mispriced, or awaiting a materially different weather setup.

A trader watching this programmatically would usually key off the forecast-to-observation gap: ingest the station’s live updates, compare them with any short-range forecast from the same locality, and only act once the first post-noon observation confirms the day’s ceiling. The main catalysts are the temperature evolution through late morning, any change in cloud or wind that caps heating, and the publication timing of the source table, since the market rules require the final reading to come from that feed. London’s recent weather coverage has also shown how quickly southern England can move from ordinary summer conditions to a hot spell, so the practical question is whether today’s London City Airport maximum ever approaches the market’s band before the settlement window closes.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Bot UK, which mirrors the Polymarket order book directly.

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

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.

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%.