Highest temperature in London on May 30?

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Market context

The highest temperature recorded at London City Airport on 30 May 2026 will determine the resolution of this market. Historical May data for the station shows that temperatures on this date typically range between 15°C and 22°C, with an average high around 19°C. The 0% crowd probability suggests traders expect the outcome to fall outside the uppermost temperature bands offered, though this reflects uncertainty about which specific range will be selected rather than confidence in any particular outcome.

London's late-May weather patterns are shaped by Atlantic systems and occasional continental air masses pushing northeastward. The airport station, located on the Thames estuary, experiences maritime influence that moderates extremes compared to inland locations. Records from the past decade show that temperatures exceeding 25°C on this date are uncommon but not unprecedented; the station recorded 26.1°C on 30 May 2015. Traders should monitor long-range forecasts from the Met Office and European models as the settlement date approaches, though such forecasts beyond two weeks carry substantial uncertainty. Seasonal factors—including soil moisture, cloud cover patterns, and the strength of any high-pressure systems—will be the primary drivers of whether temperatures trend toward the cooler or warmer end of the typical May range.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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 fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.