Highest temperature in London on July 6?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 6 July 2026 is the real-world event this market resolves, with the current crowd-implied probability sitting at 0% for the YES outcome. This stark pricing suggests the market believes the peak will fall below the 30°C threshold, despite the Met Office noting that July is statistically the warmest month in the capital and recent heatwaves have pushed temperatures well above 30°C[2]. Historical data shows average July peaks of 23°C, yet the 2022 record of 40.2°C at Heathrow demonstrates the volatility possible during summer heatwaves[2]. Just two days prior, on 4 July, a similar market resolved at 29°C, indicating that temperatures are already hovering near the critical band[1].

Traders must watch the immediate forecast for a significant burst of summer heat building through 5–7 July, with temperatures predicted to climb to 31°C on Friday and potentially 32°C by midday on Saturday[3]. The Met Office has updated its forecast for London City Airport, predicting a maximum temperature of 32°C for today, which directly challenges the 0% probability pricing[7]. Isolated thunderstorms could develop as the heat builds, but the dominant trend is long periods of sunshine and very warm afternoons with limited overnight cooling[3]. The resolution source, Wunderground, will capture the highest temperature for all times on this day, making the afternoon peak the decisive factor for the contract outcome[1]. On-chain mechanics on Polymarket, utilising USDC on the Polygon network and conditional tokens, will reprice this contract rapidly as NWP model updates and real-time data confirm the heatwave intensity[5]. The thin volume currently observed means that any confirmation of the 32°C forecast will trigger a fast repricing of the 30°C band probability[5].

Sources: 1 · 2 · 3 · 4 · 5

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

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.

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 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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Legit? trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.