Highest temperature in London on May 31?

Platform comparison

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, with settlement based on historical data from Weather Underground. London's late May climate typically sees daytime highs between 18°C and 22°C, though anomalies occur. The 0% crowd probability suggests traders are either uncertain about the resolution mechanism or treating this as a calibration exercise rather than a genuine weather forecast.

Historical May temperatures at London City Airport show considerable year-to-year variation. Over the past two decades, 31 May highs have ranged from approximately 15°C on cooler years to 27°C during warmer spells. The Met Office's long-range forecast methodology relies on sea-surface temperatures, atmospheric pressure patterns, and seasonal indices rather than deterministic models at this distance. Current climate patterns favour slightly above-average temperatures across the UK for late spring, though individual day forecasts remain unreliable beyond ten days.

Traders should monitor the UK Met Office's monthly outlook updates, released around the 18th of each preceding month, which provide probabilistic guidance on temperature anomalies. The North Atlantic Oscillation index and sea-surface temperature anomalies in the Atlantic will influence whether late May 2026 trends warmer or cooler than the 30-year average. Weather Underground's historical data portal confirms the exact settlement source, though traders should verify the station's operational status and data quality closer to the resolution date.

Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for Highest temperature in London on May 31? plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

Where can I trade this market with the lowest fees?

On Trump 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.

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 does it cost to trade on Trump Prediction?

Zero. Trump Prediction routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Trump Prediction triggers a quick verification flow that finishes in 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.