Highest temperature in London on June 17?

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Market context

On 17 June 2026, the highest temperature recorded at London City Airport will determine which range this market settles into. The UK Met Office publishes daily maxima for this station, which sits in East London and serves as the official observation point for this resolution. Historical June temperatures at this location typically peak between 20–25°C, though heat waves can drive readings above 28°C. The settlement window closes at midday UTC on the day itself, meaning traders must assess conditions as they develop rather than wait for final overnight data.

The 0% crowd probability reflects genuine uncertainty about which specific range will occur, not dismissal of the event. June in London has produced extremes: the 2022 heatwave saw temperatures exceed 30°C in parts of the South East, whilst cooler Junes have remained in the low 20s. Weather forecasts become reliable only 7–10 days ahead; traders currently face a six-month lead time with only seasonal climatology to guide positioning. The Met Office's long-range outlook, updated monthly, will sharpen expectations as spring progresses.

Regulatory access to this market depends on jurisdiction. German traders face restrictions under GlüStV unless using a licensed operator; US persons fall under CFTC oversight of prediction markets, though the agency's enforcement posture remains unsettled. UK-domiciled traders without KYC verification can typically trade up to £1,000 notional exposure per market, a threshold designed to balance retail participation against financial crime obligations. Verification requirements scale with position size and cumulative exposure across multiple markets.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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.

Is this market available outside the US?

Polymarket KYC 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 does it cost to trade on Polymarket KYC UK?

Zero. Polymarket KYC 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.