Highest temperature in London on May 28?

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Market context

On 28 May 2026, the highest temperature recorded at London City Airport will determine which range this market settles into. The settlement source is Wunderground's historical weather data for that specific station, measured in Celsius, with resolution occurring at 12:00 UTC on the settlement date. The current 0% crowd probability suggests traders are either uncertain about the outcome distribution or awaiting clearer atmospheric signals before committing capital.

London's late May temperatures typically range between 16–22°C, though extremes occasionally breach these bounds. The May 2022 heatwave saw London reach 28°C mid-month, whilst cooler years have produced highs around 14–15°C. Historical volatility across the past two decades shows that whilst 20–24°C outcomes dominate, tail events above 25°C occur roughly once per five years during this period. The 0% reading reflects either sparse initial liquidity or genuine difficulty in pricing a single-day event nearly two years out, where seasonal patterns offer limited predictive power without nearer-term atmospheric data.

Traders should monitor the UK Met Office's seasonal outlook updates through early 2026, which typically refine May forecasts by late April. Broader climate patterns—including Atlantic oscillation phases and soil moisture anomalies—influence late spring temperatures across southern England. As May approaches, standard weather model consensus (GFS, ECMWF) will sharpen the probability distribution considerably. USDC settlement mechanics on btc-prediction.bet mean resolution depends entirely on Wunderground's historical archive accuracy; traders should verify the station's operational status and data continuity before significant position-building.

Methodology

This page reads Highest temperature in London on May 28? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed for comparison. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

Where can I trade this market with the lowest fees?

On BTC 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?

BTC 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'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.

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.