Highest temperature in London on June 9?

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Market context

On 9 June 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges, measured in degrees Celsius. The Polymarket contract currently prices all temperature brackets at 0% YES, reflecting either extreme illiquidity or a technical settlement state rather than genuine market conviction about any particular outcome. Resolution will depend on historical weather data from Wunderground's London City Airport Station records, captured across the full calendar day through the settlement window closing at midday on 9 June.

London's June temperatures typically range between 15°C and 23°C, though the city has recorded highs exceeding 30°C during heatwaves in recent years. The 2022 heatwave saw temperatures reach 40.3°C across parts of the UK, though London City Airport itself recorded lower peaks. Historical June data from the same station shows most days cluster in the low-to-mid 20s Celsius. Understanding these seasonal baselines and the airport's specific microclimate—which can differ from central London readings—matters for calibrating expectations against whatever temperature brackets the market ultimately offers.

Traders should monitor UK Met Office forecasts issued in the week preceding 9 June, as these will provide the most reliable guidance on whether atmospheric conditions favour typical early-summer temperatures or anomalous warmth. Longer-range models become increasingly uncertain beyond ten days, but any significant high-pressure system developing over the British Isles in early June could shift outcomes materially. The settlement mechanism depends entirely on Wunderground's historical records, making the data source itself the critical dependency rather than real-time forecasting.

Methodology

This page reviews Highest temperature in London on June 9? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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 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.

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.

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.