Highest temperature in London on August 15?

Platform comparison

Market context

On 15 August 2026, the highest temperature recorded at London City Airport will fall within one of several defined ranges. The crowd currently assigns zero probability to the YES outcome, suggesting either extreme confidence in a specific temperature band or genuine uncertainty about which range will capture the day's peak reading. Resolution hinges on the Daily Observations table from Weather Underground rather than summary figures, a distinction that occasionally produces materially different values from headline reporting.

London's August temperatures have historically clustered between 20–28°C, with extremes rare but not unprecedented. The city recorded 40.3°C in July 2022, demonstrating that heat waves can breach long-standing records, though August typically runs slightly cooler than peak summer. The zero probability assigned here likely reflects either a market consensus around a particular temperature band (most probably the 20–25°C or 25–30°C ranges given typical August conditions) or sparse liquidity creating artificial pricing. Historical volatility suggests meaningful weather variation remains possible even within summer months.

Traders should monitor the Met Office's extended forecast from late July onwards, particularly any alerts for high-pressure systems or heat waves developing across northern Europe. The UK's August weather patterns often track Atlantic systems and continental heat drifts, both of which can shift temperatures substantially. Recent summers have shown increased frequency of above-average heat, though individual day outcomes remain genuinely uncertain. The specific reliance on City Airport station data—rather than other London monitoring points—means localised conditions at that site will determine settlement, potentially creating discrepancies from broader London readings.

Methodology

This page reviews Highest temperature in London on August 15? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Who Will Win 2026, which mirrors 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

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.

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?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.