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 weather station will fall into one of several defined ranges, measured in degrees Celsius. The settlement will draw from Wunderground's historical weather database for that specific location and date, with the resolution window closing at 12:00 UTC on the day itself. This market operates under UK Gambling Commission oversight for domestic traders, though cross-border participation triggers additional regulatory considerations. Under German GlüStV (gambling licensing statute), prediction markets on weather events are classified as financial derivatives rather than games of chance, exempting them from standard gaming tax where the operator holds appropriate licensing. US CFTC jurisdiction extends to any US-domiciled trader accessing this contract; the agency treats weather derivatives as commodity futures, requiring either exchange registration or a valid exemption. For traders in jurisdictions permitting KYC-free participation up to £1,500 notional exposure, this market remains accessible without identity verification, though settlement and withdrawal may require later verification depending on aggregate account activity.

London's late May temperatures typically range between 16–22°C, with historical data from the Met Office showing mean highs around 19–20°C for this period. The 0% crowd probability suggests either extreme confidence in a specific outcome already priced into other ranges, or sparse initial liquidity. May weather in London is sensitive to Atlantic pressure systems; high-pressure ridges from the Azores can drive temperatures above 23°C, whilst northwesterly flows keep readings closer to 15°C. Traders should monitor the UK Met Office five-day forecast issued on 24–25 May, which will provide the most actionable signal for late-month temperature distribution. Recent springs (2023–2025) have shown increasing volatility in May temperatures across southeast England, with occasional warm spells pushing into the mid-20s Celsius.

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

Is this market available outside the US?

Polymarket Tax UK 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 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.