Highest temperature in London on July 6?

Platform comparison

Market context

On 6 July 2026, the real-world event determining this market’s outcome is the highest temperature recorded at London City Airport, measured in degrees Celsius. In prediction markets, a YES share pays out if the temperature falls within the specified range, while a NO share pays out if it does not. The current crowd-implied probability of YES is 0%, suggesting traders believe the temperature will not hit the target range, though this reflects collective sentiment rather than certainty.

Historically, July is London’s hottest month, with average highs around 22°C (72°F) at London City Airport, though extreme days can reach 29°C or higher. For instance, recent forecasts for 7 July 2026 show highs of 29°C with sweltering conditions, indicating that temperatures near the upper range are plausible [1][6]. The 0% probability may stem from the specific range being unusually high, rather than a lack of heat potential.

Traders should monitor daily weather bulletins from the Met Office and Wunderground, which serve as the official resolution source [5]. Key catalysts include heatwave announcements from the UK Health Security Agency and real-time temperature updates from the airport’s station. A recent forecast for London City Airport noted a high of 29°C with clear skies, reinforcing that heat is possible but may not meet the market’s threshold [2][3]. No moralising is needed; the facts guide the trade.

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'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.

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 reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.