Highest temperature in London on May 26?

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Market context

The highest temperature recorded at London City Airport on 26 May 2026 will determine the settlement of this market. The resolution source is historical weather data from Wunderground, capturing the peak temperature in Celsius across all daylight and evening hours on that specific date.

London's late May temperatures typically range between 15–22°C, with occasional warm spells pushing into the mid-20s. Historical records show that temperatures exceeding 25°C on this date occur roughly once per decade, whilst readings above 28°C are exceptionally rare. The 0% crowd-implied probability suggests traders are pricing in either a very narrow temperature band or reflecting genuine uncertainty about which range will ultimately resolve. Comparable late-spring forecasting on prediction markets has shown wide divergence between early-season odds and actual outcomes, particularly when Atlantic weather systems or continental air masses shift unexpectedly in the fortnight before settlement.

The key catalyst is the Met Office's extended forecast, typically issued with meaningful confidence 10–14 days before the settlement date. Traders should monitor late May 2026 pressure patterns and any early signals of heat transport from the south. Jet stream positioning in early May will be the primary driver of whether cooler Atlantic conditions or warmer European air masses dominate the UK on the 26th. Current seasonal models remain too distant to provide reliable guidance, meaning this market will likely see significant repricing once deterministic forecasts emerge in mid-May.

Methodology

This page reviews Highest temperature in London on May 26? 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 PolyGram — 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

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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.

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How fast are USDC deposits?

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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.