Highest temperature in London on June 4?

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Market context

The market is pricing the highest temperature recorded at London City Airport on 4 June 2026. The crowd has assigned 0% probability to the YES outcome, suggesting consensus that the temperature will fall below the threshold implied by the market's resolution brackets—though the specific temperature bands are not detailed in the available information.

London's June weather typically ranges from 15°C to 22°C, with occasional warm spells pushing into the mid-20s. Historical data from the Met Office shows that temperatures exceeding 25°C in early June occur roughly once every three to four years in the capital, whilst readings above 28°C are considerably rarer at this time of year. The 0% crowd probability suggests traders are anchoring to typical early-summer conditions rather than accounting for the tail risk of an unseasonable heatwave. June 2019 saw London reach 32°C, demonstrating that extreme heat is possible, though such events remain statistical outliers for this period.

The key catalyst will be the Atlantic weather pattern established by late May 2026. High-pressure systems tracking from the Azores or continental Europe can drive temperatures sharply upward, whilst Atlantic lows maintain cooler, damper conditions. The UK Met Office's extended forecast, typically issued two weeks ahead, will provide the first reliable signal of June's dominant pressure regime. Any indication of a blocking high or heat dome settling over the British Isles would represent material new information against the current consensus pricing.

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 Who Will Win, 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?

Who Will Win 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.

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.