Highest temperature in London on July 23?

Platform comparison

Market context

London City Airport’s peak temperature on 23 July will be the settlement driver, and the current crowd view of a **0% YES** looks very conservative against both climatology and the live market pricing. Polymarket’s contract is already centring on **26°C at 48%**, with **25°C at 24%**, which implies traders think a mid-20s high is the modal outcome rather than a sub-25°C reading.[2] July in London typically brings highs around **23°C** with changeable conditions and some rainfall, so a low-teens or very cool outcome would be unusual for the date.[1]

That framing matters because this market resolves on the **single highest reading** at London City Airport, not a citywide daily average, so one warmer afternoon pulse can matter more than the broader forecast. Recent July coverage has pointed to hotter spells in London, with forecasts earlier this month calling for peaks around **27°C** before thunderstorms eased the heat, which supports the idea that the upper-20s band remains plausible even if conditions cool later.[3] Analytically, the spread between the **0% YES** crowd number and Polymarket’s distribution suggests the contract is being priced like a weather-range bet rather than a binary certainty, with no clear evidence here of a sportsbook-style consensus available in the sourced material.[2]

Traders will mainly watch the final high-resolution forecast track for London City Airport, especially any shift in cloud cover, showers, or maritime wind that could cap the afternoon maximum below the mid-20s. July climate guides for London still point to warmth, with average highs around **23°C** and recurring dry, sunny periods, but the day-specific outcome depends on the exact timing of any convective rain or thunder and whether the airport station briefly spikes above the broader city forecast.[1][5] Because settlement is tied to the station reading on Wunderground, late changes in the official history feed are what ultimately matter most, not broader London headlines.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on July 23? 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

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.

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 Best Prediction Markets 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.