Highest temperature in London on May 29?

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Market context

The settlement of this market depends on the highest temperature recorded at London City Airport on 29 May 2026, measured in Celsius and resolved against Wunderground historical data. The airport station sits in East London and provides a consistent urban measurement point, though readings can vary slightly from other London locations depending on local microclimates and surface conditions.

May temperatures in London typically range between 15°C and 22°C, with historical highs occasionally reaching the mid-20s. The 0% crowd probability suggests traders are either uncertain about which specific temperature band will occur or are waiting for seasonal forecasts closer to the date. Late May sits at the transition into early summer, when high-pressure systems can occasionally push temperatures above 25°C, though such occurrences remain relatively infrequent. Comparable May days over the past decade show considerable variability; the Met Office records indicate May highs in London have ranged from around 18°C in cooler years to 26°C in warmer ones.

Traders should monitor long-range weather forecasts released in April and early May, which will provide increasingly reliable guidance on atmospheric patterns for late May 2026. The North Atlantic Oscillation and broader European pressure systems typically determine whether warm continental air reaches the UK during this period. Any significant heat warnings or unusual seasonal forecasts from the Met Office in the weeks preceding 29 May would shift market expectations materially. Settlement requires accessing Wunderground's historical archive for that specific date and station once the day has passed.

Methodology

We track Highest temperature in London on May 29? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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?

On Sport Prediction, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Sport Prediction is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on Sport Prediction?

Zero. Sport Prediction routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.