Highest temperature in London on August 2?

Platform comparison

Market context

The key real-world event is the highest **air temperature** logged at London City Airport on 2 August 2026, and the market settles against the temperature band containing that day’s peak reading from Wunderground. The contract’s current 0% YES implies the crowd is treating the top band as extremely unlikely, which matters less as a directional view than as a reminder that the exact reporting source and cut-off rules are what drive resolution here, not generic “London weather” headlines.[1]

For historical framing, London summer highs usually cluster in the mid-to-high 20s Celsius, so a narrow set of adjacent buckets often carries most of the probability mass on these daily-temperature markets.[1][15] Current public forecasts for 2 August point to around 27°C in London, with some outlets showing 28°C and others closer to 26°C, which is the kind of spread that programmatic traders typically model by mapping each forecast service to the market’s discrete outcome bands and then updating orders when consensus shifts by a degree.[1][2][3][7]

The practical catalysts are the intraday forecast refreshes, cloud cover changes, and the timing of any residual moisture or breeze that could cap the afternoon high by one bucket either side of the modal estimate.[1] Because the market resolves off the highest reading at London City Airport, traders watching it through bots or conditional orders should focus on the station-specific feed and the publication cadence of the final daily data, since the market cannot settle until after the following day’s first datapoint appears.[1]

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

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.

Do I need to KYC for this market?

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

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.