Highest temperature in London on July 3?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 3 July 2026 will determine the outcome of this contract, with the market currently pricing the "YES" condition at 0%. This implies the crowd believes the peak temperature will fall outside the specific range being traded, likely due to expectations of a cooler day or a mismatch with the defined threshold. On-chain, the position is settled in USDC on the Polygon network using conditional tokens, where liquidity providers earn fees while traders bet on the meteorological data sourced from Wunderground.

Historical patterns for London in July show average daytime highs of 23°C, yet Met Office records confirm that sustained heatwaves frequently push temperatures above 30°C, with a record 40.2°C hit at Heathrow in July 2022[1]. Recent climate data for 2026 suggests at least one prolonged scorcher is likely, where mercury climbs well above 30°C, making the current 0% probability a bold contrarian stance against typical summer volatility[1]. The humidity in the capital can also make a 22°C afternoon feel significantly warmer, though the resolution relies strictly on the dry thermometer reading at EGLC[1].

Traders should monitor the Met Office daily forecasts for London City Airport, which currently predict a maximum of 24°C for the day, alongside real-time observations showing a high of 26°C earlier today[2][8]. The primary catalyst is the official Wunderground dataset release, which will be the sole resolution source, and any sudden shifts in southerly wind patterns that could alter the thermal profile[2]. While the average high for July 2026 is forecast between 71°F and 87°F, the specific dependency on the 3 July reading means a single cloud cover event could invalidate the "YES" bet entirely[6].

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 Polymarket Legit?, 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

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 Polymarket Legit?. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.