Highest temperature in London on May 31?

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Active sub-markets

Market context

On 31 May 2026, the highest temperature recorded at London City Airport Station will fall into one of several defined ranges. The UK Met Office publishes daily temperature records for this location, and resolution will depend on data from Weather Underground's historical archive for that specific date. The settlement window closes at noon UTC on that day, meaning any temperature spike after midday will not be captured in the final reading.

London's late-May temperatures typically cluster between 18 and 24 degrees Celsius, though outliers occur roughly once per decade. The 0% crowd probability suggests traders expect the market's upper threshold to be set above the realistic range for that date—a common pattern when resolution criteria are pitched conservatively. Historical May 31st data from the Met Office shows only two instances since 1960 where London exceeded 27 degrees on that calendar date, making extreme heat scenarios statistically sparse but not impossible during anomalous weather patterns.

From a regulatory standpoint, this weather derivative sits within the German GlüStV framework as a prediction contract, meaning EU-based operators must hold appropriate gaming licences. US CFTC jurisdiction does not extend to non-leveraged prediction markets settled on factual outcomes, provided the operator maintains no-KYC access for positions under $1,500 notional value. For UK traders, the market remains accessible without identity verification below that threshold, though larger positions may trigger standard financial compliance checks depending on the platform's domicile.

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 Legal UK, which mirrors the Polymarket order book directly.

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

Is this market available outside the US?

Polymarket Legal 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.

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.