Highest temperature in London on May 31?

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Market context

On 31 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The market currently prices all outcome ranges at 0% probability on Polygon, suggesting either insufficient liquidity or a technical settlement concern rather than genuine uncertainty about whether London will record *some* temperature that day. Resolution hinges on Wunderground's historical weather data for that specific station, converted to Celsius, with the settlement window closing at noon UTC on the day itself.

London's late May temperatures typically range between 16°C and 22°C, based on thirty-year climate normals. The highest temperature ever recorded in May at London City Airport sits around 28°C, an outlier driven by unusual high-pressure systems. Most years see peak May temperatures cluster in the 19–23°C band. The 0% crowd probability likely reflects the market's nascent state rather than any expectation of anomalous conditions; traders should examine historical volatility in late-May weather patterns and whether comparable markets on other UK stations show similar pricing distortions.

The UK Met Office publishes extended forecasts roughly ten days ahead, with increasing confidence from five days out. Late May weather in London typically depends on Atlantic storm systems and occasional continental air masses pushing northward. Traders should monitor early-June forecasts from late May onwards, though the settlement window's noon cutoff means real-time conditions matter more than predictions. Any unusual heat dome or cold snap affecting northern Europe in late spring would shift expectations materially, though such events remain statistically uncommon for this period.

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 Polymarket Legit? — 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

Is this market available outside the US?

Polymarket Legit? 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.

What does it cost to trade on Polymarket Legit??

Zero. Polymarket Legit? 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.