Highest temperature in London on August 1?

Platform comparison

Market context

Polymarket prices this contract at **0% YES** today, so the on-chain market on Polygon is effectively saying there is no live premium for any specific high-temperature band at London City Airport on 1 August 2026. In practical terms, traders are holding USDC-backed conditional tokens against a Wunderground settlement source, with the payoff depending on the single highest reading posted for the day rather than an average or midnight-to-midnight headline temperature.

For context, London’s 1 August highs are often mild rather than extreme: WeatherSpark says the city’s typical range on that date is about 60°F to 74°F, while broader London climate records show August can still produce sharp spikes, including 37.5°C in the city’s long-run records and 38.1°C at Kew Gardens on 10 August 2003.[1][9][7] That mix matters for reading a zero-priced outcome: a 0% quote usually reflects either stale pricing, very low liquidity, or a market that has not yet attracted informed order flow, not a statement that the underlying weather cannot land in a given band.

A trader watching this market would focus on UK Met Office updates, airport-level forecasts, and any late-model shifts in the days before settlement, because the resolution is tied to the *highest* temperature logged at London City Airport, not the forecast for central London.[2][8] The contract also has a timing wrinkle: Polymarket says revisions are considered only until the first datapoint for the following date is published, so late adjustments to the Wunderground history feed can still matter if they arrive before the cutoff.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on August 1? 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

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

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 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 Kalshi 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.