Highest temperature in London on May 26?

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Market context

On 26 May 2026, the highest temperature recorded at London City Airport will determine which range this market resolves to. The settlement window closes at midday UTC, with Wunderground's historical weather data serving as the authoritative source. Current crowd-implied probability sits at 0%, suggesting traders are not yet positioning significantly across any temperature band, despite the event being roughly eighteen months away.

London's May temperatures have historically clustered between 15–22°C, with occasional peaks above 25°C during warm spells. The Met Office's thirty-year average for late May highs in central London is approximately 20°C. Notably, May 2022 saw temperatures exceed 28°C on several days, whilst May 2023 remained cooler at around 18–20°C. These variations underscore the difficulty in locking in a single range this far in advance; seasonal weather patterns and broader atmospheric conditions remain highly uncertain at an eighteen-month horizon.

Traders should monitor spring 2026 climate forecasts as they emerge, particularly from the Met Office and European Centre for Medium-Range Weather Forecasts (ECMWF), which typically gain accuracy within three to four months of the target date. The North Atlantic Oscillation and broader jet-stream positioning in late May will influence whether high-pressure systems deliver warm continental air or cooler Atlantic systems dominate. No scheduled announcements directly trigger this market; resolution depends entirely on observed conditions on the day itself. Early positioning may reflect longer-term climate trends rather than near-term meteorological signals.

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

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?

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.

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.

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.