Highest temperature in London on May 27?

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Market context

On 27 May 2026, the highest temperature recorded at London City Airport Station will fall into one of several defined ranges, measured in degrees Celsius. The settlement will draw from Wunderground's historical weather database, which logs daily highs at this specific monitoring location in East London. The 0% crowd probability suggests traders currently expect no outcome to materialise within the lowest temperature bracket offered, though the market structure accommodates all plausible May conditions for this site.

London's late-May temperatures typically range between 18–22°C, with occasional warm spells pushing toward 25°C. Historical data from the Met Office shows that temperatures exceeding 28°C in late May occur roughly once per decade at London City Airport. The current zero probability assigned to the lowest range reflects baseline seasonal expectations rather than any forecasting consensus; comparable May markets on other UK weather stations have historically distributed probability across multiple mid-range brackets, with tail outcomes receiving minimal backing.

Traders should monitor the UK Met Office's extended forecast from mid-May onward, particularly any high-pressure systems or Atlantic weather patterns that could drive anomalous warmth into the south-east. The settlement window closes at 12:00 UTC on 27 May, meaning only temperatures recorded up to that point count toward resolution. From a regulatory perspective, this market operates under German GlüStV provisions where applicable to EU-based participants, whilst US CFTC reach extends to American traders; the no-KYC threshold of $1,500 applies to cumulative positions across all weather markets on this platform, meaning traders can access this market without identity verification provided their total exposure remains below that limit.

Methodology

We track Highest temperature in London on May 27? 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

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 does it cost to trade on Polymarket Tax UK?

Zero. Polymarket Tax UK 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.

Do I need to KYC for this market?

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