Highest temperature in London on August 16?

Platform comparison

Market context

On 16 August 2026, the highest temperature recorded at London City Airport will determine which range this contract settles into. The market currently prices all temperature bands at 0% probability on Polygon, suggesting either extreme illiquidity or a technical issue with the conditional token structure. Settlement hinges on Weather Underground's Daily Observations table rather than the Day High & Low summary—a distinction that matters when station equipment records micro-fluctuations or when different measurement protocols yield conflicting figures. The USDC-denominated contract will resolve once the settlement window closes at 12:00 UTC on the resolution date.

London's August temperatures have historically clustered between 20–27°C, with extremes rarely exceeding 30°C except during heat waves. The summer of 2022 saw the UK's record high of 40.3°C, though London itself peaked at 40.1°C on 19 July that year. City Airport, located in Newham with exposure to the Thames estuary, typically records slightly cooler readings than central London due to proximity to water. August 2023 saw highs around 24–26°C across the capital, providing a reasonable baseline for typical conditions.

The UK Met Office publishes extended forecasts from late July onwards, and any heat-dome warnings or Atlantic blocking patterns would emerge in early August 2026. Traders should monitor the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble runs and the Met Office's long-range outlook for signals of anomalous warmth. Seasonal climate patterns, including any La Niña or El Niño influence, could shift August's temperature profile, though such effects remain uncertain at the two-year horizon.

Methodology

This page reviews Highest temperature in London on August 16? 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 Polymarket Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

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.

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.