Highest temperature in London on June 9?

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Market context

The settlement hinges on the peak temperature recorded at London City Airport on 9 June 2026, with the crowd currently assigning zero probability to any outcome. London's June temperatures typically range between 18–23°C, though the airport station—situated in the Docklands area with limited tree cover—often records readings 1–2°C higher than central London averages. Historical data from the Met Office shows that temperatures exceeding 25°C on a single June day occur roughly once every three to four years in the capital, whilst readings above 28°C remain uncommon events for early summer.

The 0% implied probability reflects genuine uncertainty rather than consensus that mild conditions are assured. June weather in southern England depends heavily on Atlantic pressure systems and whether continental air masses penetrate northwestward; forecasts beyond ten days carry substantial margin for error. The UK Met Office and European Centre for Medium-Range Weather Forecasts will issue their most reliable guidance in late May, roughly two weeks before settlement. Any significant heatwave signal emerging in early June forecasts—particularly if high-pressure systems stall over the continent—would shift market expectations materially. Traders should monitor whether the jet stream positioning favours warm southerly flow or cooler Atlantic influences during the settlement window.

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

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.

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, Who Will Win 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.