Highest temperature in London on May 26?

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Market context

The settlement hinges on the maximum temperature recorded at London City Airport on 26 May 2026, with the crowd currently assigning zero probability to any outcome. This absence of trading activity reflects the market's distance from resolution rather than confidence in a particular temperature band. London's late May weather typically ranges between 15–22°C, though the city has recorded highs of 28–29°C during warm spells in this period. The 0% crowd probability suggests either minimal trader participation or an expectation that the market will remain illiquid until closer to the settlement date.

Historical May temperatures at London City Airport show considerable variability. Over the past two decades, 26 May has produced highs ranging from 16°C to 25°C, with most years clustering around 18–21°C. The Met Office's long-range forecasts, typically available from late April, will provide the first substantive signal for positioning. Traders should monitor the North Atlantic Oscillation and jet stream positioning in early May, as these drive whether continental warmth reaches the UK or Atlantic systems dominate. Recent springs have shown increased volatility; the May 2022 heatwave pushed temperatures above seasonal norms across southern England, establishing precedent for outlier outcomes.

The primary catalyst is the UK Met Office's extended outlook, usually issued 10–14 days before settlement. Atmospheric pressure patterns in the week preceding 26 May will determine whether high-pressure systems stall over the British Isles or low-pressure systems bring cooler, wetter conditions. Early May's actual temperature trajectory will offer traders their clearest entry point for assessing whether the range containing the eventual high is undervalued relative to historical frequency distributions.

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

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.

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.

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.