Highest temperature in London on May 27?

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Market context

The market is pricing zero probability that London's highest temperature on 27 May 2026 will fall into any single range bracket, which reflects the inherent difficulty in forecasting a specific day's peak temperature nearly eighteen months in advance. Polymarket's conditional token structure on Polygon means traders are committing USDC against discrete temperature bands—likely spanning 15–25°C, 25–30°C, and 30°C+—with settlement determined by the highest reading recorded at London City Airport weather station on that date. The current 0% pricing suggests either thin liquidity across all ranges or genuine uncertainty about which bracket will resolve in the money.

Historical May temperatures in London show considerable variability. The UK Met Office records indicate that late May highs typically range between 18–22°C, though the month has seen peaks above 28°C during warm years. The 2022 heatwave saw May temperatures climb sharply, whilst cooler springs like 2013 kept readings closer to 16–18°C. This seasonal spread—roughly 12°C between typical lows and occasional highs—explains why traders face genuine difficulty pinpointing a single range without seasonal forecasting models or longer-range climate data.

Traders monitoring this contract should watch the UK Met Office's seasonal outlook updates, released quarterly, which provide probabilistic guidance on temperature anomalies for the following months. Spring 2026 Atlantic Oscillation patterns and sea surface temperature anomalies in the North Atlantic will influence whether May leans warmer or cooler than the thirty-year average. The settlement window closes at 12:00 UTC on 27 May, giving traders only the morning's data before resolution, so early-season weather patterns emerging in April and May will be the primary catalysts for price movement.

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 Polymarket Legit?, which mirrors the Polymarket order book directly.

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 Polymarket Legit?, 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 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.

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.