Highest temperature in London on June 19?

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Active sub-markets

Market context

London City Airport is the settlement point, so the relevant question is whether the day’s highest reading clears the upper end of the expected range. The market is currently pricing almost no chance of an extreme outcome, and that is consistent with late-day weather around east London showing modest temperatures rather than heatwave conditions; BBC Weather listed a Friday high of 25°C with precipitation not expected, while its observation at the airport was 13°C with southerly wind and high humidity.[2] Historical context also leans against a large spike: WeatherSpark describes London City Airport’s warm season as relatively short, running from mid-June to early September, with average daily highs only just above 67°F.[1]

For traders, the main catalysts are the intraday forecast updates and whether cloud, showers, or wind shifts change the afternoon peak before the 12:00Z settlement window closes. The Met Office forecast for London City Airport has pointed to a daily high of 18°C and a maximum feels-like temperature of 18°C, while The Weather Network’s airport feed showed light rain, scattered showers tapering off late afternoon, and a much lower high of 16°C.[7][3] Those readings imply the market would need a material forecast miss to move into a higher temperature band. The key dependency is the official Wunderground daily history entry for EGLC, which will determine the recorded maximum for the station on the day.[6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 19? 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Sport Prediction, 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?

Sport Prediction 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.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Sport Prediction triggers a quick verification flow that finishes in minutes.