Highest temperature in London on August 14?

Platform comparison

Market context

The market seeks to identify the highest temperature recorded at London City Airport on 14 August 2026, measured in degrees Celsius via Weather Underground's Daily Observations table. The current crowd-implied probability of 0% suggests traders expect the eventual settlement range to fall outside whatever threshold defines a "YES" resolution, though the specific temperature band triggering affirmative settlement remains unstated in available market documentation.

August temperatures at London City Airport typically range between 18°C and 26°C, with historical highs occasionally reaching 28–30°C during heat waves. The Met Office's long-term climate data shows that extreme heat events (above 32°C) occur infrequently in London during mid-August, though the summer of 2022 produced several days exceeding 35°C across south-east England. The 0% crowd probability suggests either that traders expect a relatively cool day or that the resolution threshold is set sufficiently high to make affirmative outcomes statistically unlikely based on seasonal norms.

Traders monitoring this contract should track the UK Met Office's extended forecast as August 2026 approaches, particularly any alerts for heat waves or anomalous pressure systems that might drive temperatures above seasonal averages. The resolution methodology—explicitly prioritising Weather Underground's Daily Observations table over the Day High & Low summary—introduces a technical dependency; discrepancies between these sources have occasionally caused disputes in weather-based markets. Cross-platform comparison with sportsbook weather derivatives or other prediction markets covering UK August temperatures may reveal whether the 0% probability reflects genuine consensus or represents an outlier position.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

UK Frequently Asked Questions

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 Best Prediction Markets UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

What are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.