Highest temperature in London on August 5?

Platform comparison

Market context

Polymarket has this contract at **0% YES** right now, so the market is pricing virtually no chance that London City Airport’s recorded daytime high will land in the winning range for 5 August. In practical terms, the position settles in USDC on Polygon through conditional tokens, and the actual result will come from Wunderground’s highest temperature reading for London City Airport Station on the day, not from a citywide average or an informal forecast.

The current setup is awkward for traders because most public forecasts point to a warm, fairly ordinary August day rather than an extreme outlier. Recent forecasts cluster around highs of about **25°C to 26°C** for London, with source ranges in the low-to-mid 20s and only modest wind and rain risk[1][3][13]. Seasonal comparison also matters: August in London is usually comfortable, with typical daytime highs around **21°C to 22°C** and lows near **13°C to 14°C**, so a very high reading would need a clear above-normal spike rather than a routine warm spell[2][7][11].

For catalysts, the key watchpoints are the morning evolution of cloud cover, any afternoon sunbreaks that let the airport station warm quickly, and whether convection or passing showers cap the maximum before the settlement window closes at noon UTC. Forecast providers currently lean dry-to-partly cloudy, which supports a steady climb but not necessarily a breakout, while reported winds and humidity suggest the day may feel milder than the thermometer reads[1][3][4]. On-chain, that means traders are mostly reacting to weather updates and model shifts rather than to any external event schedule or discretionary announcement.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Alternative UK, which mirrors the Polymarket order book directly.

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Alternative UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Alternative UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.