Highest temperature in London on May 30?

Platform comparison

Active sub-markets

Market context

The settlement of this contract hinges on the highest temperature recorded at London City Airport on 30 May 2026, measured in Celsius and resolved via Weather Underground's historical data. The 0% implied probability across prediction markets suggests traders are either absent from the contract or treating the outcome as effectively certain to fall outside whichever temperature band this particular YES option represents. Without visibility of the specific temperature threshold attached to this YES resolution criterion, the nil probability reflects either an extremely high or extremely low temperature boundary that historical May conditions in London make implausible.

London's late May temperatures typically range between 14°C and 20°C, with the Met Office recording an average high of approximately 19°C for this period. Historical extremes provide calibration: the highest May temperature ever recorded in central London reached 29.9°C in 2022, whilst readings below 10°C on 30 May are rare but documented. The 0% reading suggests this YES option covers a range either above 30°C or below 5°C—both statistically unlikely for this calendar date, though climate variability and urban heat effects at the airport location warrant consideration of edge cases.

Traders monitoring this contract should track the UK Met Office's extended forecast as May 2026 approaches, particularly any anomalous weather patterns or heat advisories issued in the preceding weeks. The airport's microclimate—influenced by tarmac, buildings, and proximity to the Thames—can produce readings 1–2°C higher than surrounding areas during high-pressure systems. Real-time weather model consensus from ECMWF and GFS will sharpen probability estimates closer to settlement, though current market pricing reflects confidence in a mid-range outcome.

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Best Prediction Markets, which mirrors the Polymarket order book directly.

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 Best Prediction Markets, 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?

Best Prediction Markets 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.