Highest temperature in London on May 28?

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Active sub-markets

Market context

On 28 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement source is Wunderground's historical weather database for that specific station, measured in Celsius. The 0% crowd probability suggests traders currently see no meaningful chance of an extreme outcome, or that the market has not yet attracted sufficient liquidity to establish a consensus forecast.

London's May temperatures typically range between 15–22°C, with occasional peaks above 25°C during warm spells. Historical data from the Met Office shows that temperatures exceeding 28°C in late May occur roughly once every five to seven years in the capital, whilst readings above 30°C remain rare for this period. The current zero probability may reflect either baseline expectations for mild conditions or simply thin trading activity at market inception. Comparable weather markets on prediction platforms have shown that temperature forecasts become more accurate within 7–10 days of the settlement date, as meteorological models converge.

Traders should monitor the UK Met Office's extended outlook and European weather pattern forecasts from late April onwards, as these will signal whether high-pressure systems or Atlantic weather fronts are likely to dominate in late May. The North Atlantic Oscillation index and sea-surface temperature anomalies in the Atlantic influence UK weather patterns on this timescale. Any significant deviation from seasonal norms announced in May forecasts could shift market probabilities sharply. Settlement occurs at 12:00 UTC on 28 May, aligning with standard meteorological observation windows.

Methodology

We track Highest temperature in London on May 28? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

Where can I trade this market with the lowest fees?

On Polymarket KYC UK, 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.

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.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket KYC UK 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.