Highest temperature in London on August 19?

Platform comparison

Market context

London's weather on 19 August 2026 remains uncertain, with the settlement window still eighteen months away. The Met Office's extended forecasting capability deteriorates sharply beyond two weeks, making current probability assessments largely speculative rather than grounded in actionable meteorological data. August typically sees London temperatures ranging between 20–24°C, though heat waves can push readings above 30°C; the 2022 heatwave saw the UK record 40.3°C, though London itself peaked lower at around 37°C during that event.

Historical August temperatures at London City Airport—the specified resolution station—show considerable variability. The airport's records indicate August highs commonly fall within 21–25°C, with occasional excursions to 28–30°C during warmer years. The 0% crowd probability suggests traders are either pricing in exceptionally cool conditions or treating the distant date as too uncertain to meaningfully assess. Comparable August dates in recent years (2019–2023) produced highs between 19–28°C at the airport station, establishing a baseline range.

Traders monitoring this market should track the UK Climate Projections updates and any revision to long-range seasonal forecasts as summer 2026 approaches. The Met Office typically releases 30-day outlooks in late July, which would provide the first substantive meteorological signal. Atmospheric circulation patterns—particularly the North Atlantic Oscillation and jet stream positioning—become predictable only 10–14 days ahead, meaning meaningful probability shifts will likely emerge only in early-to-mid August 2026.

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 Prediction Today, 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

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 does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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%.