Highest temperature in London on May 31?

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Active sub-markets

Market context

The highest temperature recorded at London City Airport on 31 May 2026 will determine which temperature band this market resolves to. Historical May data for the station shows that late-spring days in London typically peak between 18–22°C, though outliers do occur. The 0% crowd probability suggests traders are pricing in an expectation that the settlement window will close before reliable forecasts materialise, or that the market itself may face technical or data-access issues before resolution.

London's late May weather patterns are shaped by Atlantic pressure systems and occasional continental warm air masses pushing north from mainland Europe. Over the past decade, 31 May temperatures at City Airport have ranged from around 15°C on cooler years to peaks near 24°C during warmer springs. The Met Office typically issues reliable 10-day forecasts roughly one week before the settlement date, which would fall in late May 2026. Traders should monitor whether the forecast confidence increases as the date approaches and whether any significant high-pressure systems are predicted to settle over the UK during that period.

The settlement mechanism depends entirely on Wunderground's historical records for the specific station. Any data gaps, station maintenance, or reporting delays could affect resolution timing. Traders should verify the data source's accessibility well before the settlement window closes on 31 May at noon UTC, as the market cannot resolve until confirmed readings are available.

Methodology

This page reviews Highest temperature in London on May 31? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Sport Prediction — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.

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.

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.