Highest temperature in London on July 13?

Platform comparison

Market context

London City Airport is forecast to reach a high of 27°C today, with the current Polymarket contract pricing a YES outcome for the highest temperature exceeding a specific threshold at just 3% [2][4]. Traders on the Polygon network are using USDC to buy and sell conditional tokens representing temperature ranges, with the 27°C bracket acting as the frontrunner at 41% probability, suggesting the market expects the day’s peak to align closely with this figure rather than spike significantly higher [2]. The settlement window closes at 12:00 UTC on 13 July 2026, locking in the final Wunderground reading for EGLC as the definitive resolution source [2].

Historically, London’s July highs average around 22°C, though extreme heatwaves have pushed temperatures past 40°C, as seen in July 2022 when Heathrow recorded 40.2°C [1][5]. The current 3% probability implies traders view a record-breaking surge as unlikely, consistent with the Met Office’s forecast of a maximum “feels like” temperature of 24°C and sunny conditions with moderate southerly winds [4]. Comparable years show July 13 typically hovering between 24–27°C, making the low YES probability a rational reflection of stable seasonal norms rather than an outlier event [1].

Key catalysts include real-time updates from BBC Weather and The Weather Network, both currently forecasting a high of 27°C for EGLC today [6][7]. Traders should monitor the 3:20 am temperature reading of 61°F (16°C) and the projected 28°C high, as deviations could shift conditional token liquidity before the 12:00 UTC settlement [9]. No major weather announcements are scheduled, but sudden shifts in wind direction or humidity could alter the final Wunderground data point, which remains the sole arbiter for market resolution [2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on July 13? 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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.