Highest temperature in London on August 6?

Platform comparison

Market context

Polymarket is pricing this London City Airport temperature contract at **0% YES** right now, so the market is effectively saying the current information set does not support a hit in any of the upside bins. In practical terms, buyers are funding the position in **USDC** on **Polygon**, and the payout will depend on the final Wunderground reading for the station, where the market resolves to the temperature range containing the day’s highest recorded value.

For context, London in August usually sits in the high teens to low 20s Celsius, with AccuWeather’s August page showing a forecast profile around the mid-20s at the start of the month and the long-run seasonal backdrop remaining much cooler than the top bins in this market.[1][12] A useful comparison is the 2026 UK summer so far: the Met Office said daily maximum temperatures had been 2.1°C above average across the UK by mid-July, while separate reports in late spring and June showed the country did experience brief heat spikes above 32°C and even 35°C elsewhere, so a warm burst cannot be ruled out entirely.[15][14][19]

The main catalysts are the short-range forecast updates and whether any continental heat plume reaches south-east England before the settlement cutoff. Recent coverage points to a generally mild London setup for 6 August, with forecasts around the low 20s Celsius and only limited rain risk, while broader commentary on August suggests the timing of any late-summer hot spell is still uncertain and model-dependent.[3][18] For traders, the key issue is whether that forecast can translate into a higher *daily maximum* at London City Airport before the Wunderground history page finalises, because once the day’s data are locked in, later revisions do not affect resolution.[6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on August 6? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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 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.

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%.