Highest temperature in London on August 21?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 21 August 2026 will determine this market's resolution, with measurements taken from Weather Underground's Daily Observations table rather than summary figures. The settlement window closes at midday UTC on that date, capturing the full diurnal cycle up to the resolution point.

London's August temperatures have historically ranged between 18°C and 32°C, with the city's record high for the month standing at 37.3°C set in 2022. The 0% crowd probability suggests traders expect a notably cool day relative to typical late-summer conditions, or that the market reflects uncertainty about which specific temperature band will be recorded. August 2025 saw London peak at 27°C on the 21st, providing a recent comparable for typical conditions on this calendar date.

The Met Office's seasonal forecasts and any significant weather patterns developing in early August 2026 will shape expectations. Traders should monitor whether Atlantic weather systems or continental high-pressure systems are positioned to influence the UK during this period. The specific resolution source—Weather Underground's Daily Observations at London City Airport rather than alternative stations or summary data—creates a technical dependency; historical discrepancies between observation tables and day-high summaries have occasionally exceeded 1°C, which could affect marginal outcomes.

Methodology

Sports-specific comparison page for Highest temperature in London on August 21?. Polymarket's live quote (Polygon order book) plus platform attributes for the three reference venues. Sports markets reward liquidity — Polymarket and Betfair are materially deeper than Kalshi or Manifold.

Resolution & payout

Sports markets typically settle on official final-whistle plus league confirmation. Polymarket uses UMA Optimistic Oracle with a source URL per contract — usually official league data feeds or ESPN/Soccerway. Two-hour dispute window, then smart-contract payout in USDC.

FAQ

Are prediction markets better than sports betting?

Prediction markets tend toward tighter odds than bookmakers because they use peer-to-peer exchange rather than bookmaker margin. On major matches, Polymarket quotes typically sit 2-5% closer to the true probability model than bet365 or DraftKings.

When do sports markets resolve?

Typically within hours of the official final whistle. Polymarket uses UMA Optimistic Oracle with source URLs pointing at official league data feeds — e.g. the Premier League for EPL markets, UEFA for Champions League, FIFA for World Cup.

Which sports markets are available?

Football (soccer) dominates — Champions League, World Cup, Premier League, La Liga, Bundesliga — followed by NFL, NBA, tennis Grand Slams, Formula 1, boxing/MMA. Resolution via official league source confirmation.

How fast do sports winnings settle?

Once the official league outcome is logged in the UMA Oracle (typically 1-2 hours after the final whistle), Polymarket's smart contract triggers USDC payout. To your wallet within minutes.

Can I import form data and lineups?

This page shows the live Polymarket quote as an implied probability. Form data and lineups must be researched separately via sports data providers (e.g. Soccerway, ESPN, FBref) — we surface the market probability, not the sport analysis.