Highest temperature in London on June 19?

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Market context

On 19 June 2026, London City Airport is forecast to be sunny with a gentle breeze and a high of 86°F (30°C), yet the prediction market for the highest temperature on this date currently prices the YES outcome at 0% probability. This stark divergence between the on-chain conditional token price and the underlying weather reality suggests the market is either mispricing the event or betting on a specific temperature range that excludes the forecasted 30°C. Traders on Polygon using USDC must scrutinise whether the 0% price reflects a genuine belief that temperatures will stay below the threshold or a liquidity gap in the market.

Historically, late June at London City Airport falls within the warm season, which runs from 16 June to 8 September, with average daily highs exceeding 67°F (19°C) [4]. While the current forecast of 30°C is notably warm, comparable years show that temperatures can fluctuate significantly, and the 0% market price implies a conviction that the peak will not breach the specific resolution range, perhaps due to the high humidity of 88% and moderate visibility currently observed [1]. The market’s refusal to price in the sunny forecast suggests a deep scepticism about the reliability of the Wunderground resolution source or the specific temperature bracket defined in the contract.

Key catalysts for traders include the official release of the daily high temperature on Wunderground, which will settle the contract at 12:00 UTC on 19 June 2026, and any sudden shifts in the southerly wind or falling pressure of 1012mb [1][3]. Traders should monitor the Met Office’s seven-day forecast for London City Airport, as any unexpected cloud cover or rain could lower the peak temperature below the threshold, validating the current 0% price [6]. The settlement depends entirely on the highest recorded temperature for all times on this day, making real-time monitoring of the airport’s weather station critical for on-chain positioning.

Sources: 1 · 2 · 3 · 4 · 5

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 Polymarket Scam?, 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?

Polymarket Scam? 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.

What does it cost to trade on Polymarket Scam??

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

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.