Highest temperature in London on May 23?

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Active sub-markets

Market context

The highest temperature recorded at London City Airport on 23 May 2026 will determine which temperature band this market resolves to, with settlement based on Weather Underground's historical data for that specific station and date.

London's late May weather typically ranges between 15°C and 22°C, though extremes do occur. Historical records show that temperatures exceeding 25°C on this date are rare but not unprecedented; the UK experienced a notably warm May in 2022, with several days surpassing seasonal norms. The current 0% crowd probability suggests traders expect temperatures to fall outside the highest available range, though this may reflect uncertainty about which specific band the market offers rather than a genuine forecast of unusually cool conditions. Comparable late-spring days at London City Airport have produced readings spanning 12°C to 26°C depending on the year, indicating substantial variability.

Traders should monitor the Met Office's seasonal outlook and any Atlantic weather patterns developing in spring 2026, as these drive UK temperatures weeks in advance. The settlement window closes at midday on 23 May, meaning final resolution depends on morning and early-afternoon readings rather than the full day's peak. Any unusual high-pressure systems or warm continental air masses moving northward in late May could shift outcomes materially. Real-time temperature forecasts from the Met Office and BBC Weather will become increasingly precise in the weeks immediately preceding the date, offering traders opportunities to reassess positioning as the event approaches.

Methodology

This page tracks Highest temperature in London on May 23? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. PolyGram routes every trade through to Polymarket — at 0% fees.

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 PolyGram, 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'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 PolyGram?

Zero. PolyGram 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, PolyGram triggers a quick verification flow that finishes in minutes.