Highest temperature in London on July 12?

Platform comparison

Market context

London City Airport is forecast to reach 29°C today, Sunday 12 July 2026, with sunny intervals and a moderate southerly breeze, meaning the highest temperature recorded will fall well below the 40°C threshold that historically defines extreme London heat[4][5]. On Polymarket, this contract trades at 0% probability for the YES outcome, reflecting the crowd’s consensus that today’s conditions are too mild to trigger a resolution in the upper temperature bands. The market settles on USDC via Polygon, using conditional tokens to lock positions until the 12:00 UTC cutoff, when Wunderground’s official daily high for EGLC will determine the final range[1][4].

Historically, London has only breached 40°C once, in July 2022, when Heathrow and St James’s Park recorded 40.2°C and 40.3°C respectively—events that remain outliers against July’s average high of 22°C (72°F) at London City Airport[2][6]. Even in the warmest recent years, such as 2026’s July forecast showing highs between 21°C and 31°C, temperatures at EGLC rarely exceed 32°C, making a 40°C+ outcome statistically implausible under current climate patterns[1][7].

Traders should monitor the Met Office’s 7-day forecast updates and Wunderground’s real-time hourly logs for EGLC, as any sudden shift in wind direction or cloud cover could alter the day’s peak[3][9]. With today’s humidity at 88% and pressure falling, the atmosphere is stabilising rather than building heat, further reducing the likelihood of a record spike[4]. No official heat warnings have been issued for Greater London as of 14:50 UTC, confirming the market’s zero-probability stance[3].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi UK, which mirrors the Polymarket order book directly.

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.

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