Highest temperature in London on June 19?

Platform comparison

Active sub-markets

Market context

London City Airport’s high temperature today will be set by the day’s warmest reading on the airport station’s observations, and the current crowd price of **0% YES** implies traders see the contract’s target range as very unlikely to be reached. With the market resolving to the highest temperature recorded on 19 June at London City Airport, the key comparison is not just whether London was warm, but whether the station’s peak crossed the specific Celsius band used in settlement. BBC Weather’s live observation for London City Airport showed **13°C** at the time of reporting, while its forecast for Friday 19 June pointed to **86°F** in the day, underlining a meaningful gap between current conditions and the sort of heat needed for a higher resolution band.[2]

On historical and comparable framing, London’s June climatology is warm but rarely extreme enough to make very high temperature bands routine, with WeatherSpark describing mid-June as the start of the city’s warm season rather than a peak-heat period.[6] That helps explain why prediction markets on London temperature contracts often cluster around moderate highs rather than upper-end summer spikes, and why a zero-priced outcome can still be consistent with a market expecting a warm, but not exceptional, day. Cross-platform comparison also matters: sportsbook-style weather lines, where available, typically focus on a single forecast number or threshold, while prediction markets assign probabilities across discrete bands, so a “0%” reading can reflect fine-grained distribution rather than a literal impossibility.

Traders should watch the evolution of the afternoon forecast, any late-day cloud or shower development, and the exact timing of the station’s maximum before the 12:00 UTC settlement cut-off. The Met Office and BBC Weather both cover London City Airport with live updates, and the airport-specific observations are the relevant operational inputs for this contract rather than wider London conditions.[2][7] If temperatures stay near the low-to-mid teens Celsius, the market is likely to remain compressed at the bottom end; if sunshine persists and the city warms materially above current observations, that is the main catalyst for any re-pricing away from the present 0% YES level.[2][3]

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

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 Best Prediction Markets 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?

Best Prediction Markets 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'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.

What does it cost to trade on Best Prediction Markets UK?

Zero. Best Prediction Markets UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.