Highest temperature in London on July 26?

Platform comparison

Market context

The market is pricing the highest temperature recorded at London City Airport on 26 July 2026, with settlement based on Wunderground historical data. The crowd currently assigns 0% probability to any outcome, suggesting either extreme uncertainty or a technical issue with market participation. London's July temperatures typically range between 20–27°C, though heat waves can push readings above 30°C. The settlement window closes at noon on the day itself, meaning traders must forecast conditions before final readings are confirmed.

Historical precedent shows London experiences significant temperature variability in late July. The UK's record July temperature of 40.3°C (set in 2022) occurred earlier in the month, whilst more typical late-July highs cluster around 24–26°C. City Airport, located in the Docklands with urban heat-island effects, often records temperatures 1–2°C higher than central London averages. The 0% crowd probability likely reflects low trading volume rather than genuine consensus that no temperature range will occur.

The Met Office's seasonal forecasts and any heat-dome positioning across northern Europe in early July 2026 will shape expectations. Traders should monitor Atlantic pressure systems and jet-stream patterns in the weeks preceding the settlement date, as these determine whether continental heat reaches the UK or cooler maritime air dominates. Recent summers have shown increased volatility in late-July conditions, making historical averages less reliable than real-time meteorological signals closer to the event.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.