Highest temperature in London on July 10?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 10 July 2026 is currently forecast to reach 32°C, with the Met Office confirming that sweltering conditions will persist through the week before a slight cool on Friday[2]. This real-world certainty directly contradicts the market's current 0% probability for the "25°C or below" outcome, as the atmosphere remains unstable with daytime highs unlikely to dip below 30°C until the heatwave breaks on Sunday[2].

Historical data frames this probability as a mispricing; while London's average July peak is 23°C, recent heatwaves have frequently pushed temperatures above 30°C, with a record 40.2°C hit at Heathrow in July 2022[5]. The current frontrunner for this contract is 30°C at 34%, followed closely by 29°C at 33%, suggesting the market expects a hot day rather than a cool one, which aligns with the amber heat alerts issued by the UK Health Security Agency covering London until 12 July[2].

Traders should monitor the Met Office's hourly updates for London City Airport, as the forecast predicts a peak of 33°C on Thursday followed by 32°C on Friday, with thunderstorm risks increasing later in the period[4]. The resolution source, Wunderground, will publish the first data point for 10 July only after the settlement window closes, meaning any sudden shift in the forecast towards heavy rain or a rapid temperature drop before Friday evening could alter the final outcome[1]. On-chain mechanics on Polygon using USDC will reflect these shifts instantly through conditional tokens, requiring precise timing to capitalise on the thin volume and model uncertainty inherent in this precision market[10].

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 PolyGram, 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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram 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.