Highest temperature in London on May 23?

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Active sub-markets

Market context

London's weather on 23 May 2026 will be shaped by Atlantic systems and the transition into late spring. The settlement window closes at midday, capturing the peak heating hours when maximum temperatures typically occur. Recent synoptic patterns show May in London averaging highs between 17–20°C, though individual days regularly exceed 22°C when high-pressure systems dominate. The 0% crowd probability suggests traders are either uncertain about the specific temperature bands available or treating this as a calibration exercise ahead of actual forecast data.

Historical May records at London City Airport show the station has recorded highs of 27°C and above on rare occasions, though such extremes occur in perhaps one May per decade. More typical warm May days—those exceeding 23°C—happen roughly once every two to three years during the month. The absence of any probability mass in the current market reflects the distance from the settlement date; meaningful forecasts for late May 2026 will not solidify until early May at earliest, when medium-range models converge.

Traders should monitor the UK Met Office's extended outlook in early May, which will provide the first reliable signal of whether high-pressure systems or Atlantic lows will dominate the week. Sea-surface temperatures in the North Atlantic and the North Atlantic Oscillation phase will influence whether warm continental air reaches London or cooler maritime conditions prevail. The specific temperature bands offered will determine whether the market becomes active; narrow ranges around 18–22°C would capture most plausible outcomes, whilst wider bands may attract hedging activity.

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 PolyGram, which mirrors the Polymarket order book directly.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Is this market available outside the US?

PolyGram 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.

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.

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.