Highest temperature in London on May 27?

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Active sub-markets

Market context

On 27 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement will draw from Wunderground's historical weather database for that specific station and date, with the crowd currently assigning zero probability to any single outcome—a position that typically reflects either extreme uncertainty or insufficient trader participation at this early stage.

London's May temperatures have historically clustered between 18 and 24 degrees Celsius, with occasional peaks above 25°C during warm spells. The May 2022 heatwave saw London reach 28.3°C, whilst more typical late-May days remain in the low-to-mid 20s. The 0% crowd probability here likely signals thin liquidity rather than consensus that no temperature will be recorded; comparable weather markets on Polymarket show similar flat distributions weeks ahead of settlement, with meaningful probability concentration emerging only in the final fortnight as meteorological forecasts sharpen.

Traders should monitor the UK Met Office's extended forecast from mid-May onwards, particularly any alerts for high-pressure systems or Atlantic weather patterns that could drive temperatures upward. The settlement window closes at 12:00 UTC on 27 May, meaning only temperatures recorded up to that point count—afternoon heat spikes after noon will not factor into resolution. From a regulatory standpoint, this market's accessibility depends on jurisdiction: German traders face GlüStV restrictions on prediction markets, whilst US participants encounter CFTC oversight of certain derivatives. Polymarket's no-KYC threshold of $1,500 USD applies here, permitting smaller positions without identity verification in most jurisdictions, though this does not override local prohibitions.

Methodology

This page reviews Highest temperature in London on May 27? 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 KYC UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket KYC UK, 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?

Polymarket KYC UK 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket KYC UK triggers a quick verification flow that finishes in minutes.