Highest temperature in London on August 11?

Platform comparison

Market context

On 11 August 2026, the highest temperature recorded at London City Airport will determine this market's outcome. The crowd currently assigns zero probability to any outcome occurring, suggesting either extreme confidence in a particular range or genuine uncertainty about which bracket will capture the day's peak reading. Resolution hinges on the Daily Observations table from Weather Underground rather than summary figures, a distinction that occasionally matters when intraday fluctuations create discrepancies between granular and rounded data.

London's August temperatures have historically clustered between 20–27°C, with extremes rare but not unprecedented. The 2022 heatwave saw readings exceed 40°C across parts of southern England, though London City Airport—situated in a more temperate riverside location—typically records lower peaks than inland stations. August 2003 brought sustained heat around 28–30°C to the capital, whilst cooler Augusts have seen highs barely exceed 18°C. These historical ranges suggest the market's zero-probability assessment reflects either a misunderstanding of settlement mechanics or genuine difficulty in forecasting a specific day two years hence.

Traders should monitor the Met Office's seasonal outlook for summer 2026, expected in early 2026, which may shift consensus around whether August will run warm or cool. Atlantic weather patterns and potential blocking highs in July will provide clearer signals by late July. The specific choice of London City Airport as the measurement point—rather than central London or Heathrow—matters, as riverside locations experience moderating influences. Current zero pricing likely reflects the market's youth and low liquidity rather than genuine conviction about temperature ranges.

Methodology

This page reviews Highest temperature in London on August 11? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Who Will Win 2026, which mirrors the Polymarket order book at 0% fees.

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.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Who Will Win 2026. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.