Highest temperature in London on August 13?

Platform comparison

Market context

On 13 August 2026, the highest temperature recorded at London City Airport will determine this market's outcome. The crowd currently assigns zero probability to any outcome occurring, suggesting either extreme confidence in a specific range or genuine uncertainty about which bracket 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 matters when intraday spikes occur outside standard reporting windows.

London's August temperatures have historically clustered between 20–26°C, with readings above 28°C occurring roughly once per decade during the summer months. The 2022 heatwave pushed London to 40.3°C, though such extremes remain statistical outliers. August 2026 sits two years beyond current climate data, making historical patterns the primary guide. The zero-probability reading suggests traders may be waiting for seasonal forecasts or treating this as a placeholder market pending more granular meteorological input.

The UK Met Office typically releases detailed August forecasts by late July 2026, providing the first concrete catalyst for position adjustment. Atlantic pressure systems and jet stream positioning in early August will shape whether high pressure dominates (favouring warmer readings) or Atlantic lows push cooler air southward. Any significant heatwave warnings issued in the fortnight before 13 August would shift consensus sharply. Traders should monitor European weather models from mid-July onwards, as these offer the most reliable 10-day guidance for specific dates.

Methodology

This page reviews Highest temperature in London on August 13? 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

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

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.