Highest temperature in London on August 16?

Platform comparison

Market context

On 16 August 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The market resolves using the Daily Observations table from Weather Underground rather than summary figures, a distinction that matters when intraday peaks differ from published highs. For programmatic traders, this specificity demands direct API access to Wunderground's granular observation data; relying on summary endpoints or third-party weather aggregators introduces resolution risk. The settlement window closes at midday UTC, creating a hard cutoff for temperature readings taken before noon.

August temperatures at London City Airport typically range between 18–24°C, with historical August averages around 20–21°C. The 0% crowd probability suggests the market may be pricing an unusually narrow or high temperature band, or reflects low liquidity rather than genuine forecasting consensus. Comparable August days show that readings above 25°C occur roughly once per decade; extreme heat (above 28°C) is rare but documented in recent years. Traders should cross-reference Met Office seasonal outlooks and compare this market's range definitions against climatological percentiles to identify mispriced outcomes.

Near-term weather pattern shifts depend on Atlantic jet stream positioning and high-pressure systems tracking across northern Europe in mid-August. The UK Met Office publishes extended outlooks fortnightly; the next update before settlement will arrive in late July 2026. Conditional order logic could automate position adjustments tied to official temperature forecasts released 7–10 days prior, though Wunderground's observation methodology—sensor calibration, timing of peak readings—remains the binding constraint for resolution.

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 Review UK, which mirrors the Polymarket order book directly.

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

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%.