Highest temperature in London on July 3?

Platform comparison

Market context

London City Airport is forecast to reach a maximum of 26°C on 3 July 2026, with ensemble models from the Met Office and ECMWF suggesting a peak likely between 26–27°C[1]. This aligns with historical patterns where July is London’s hottest month, averaging a high of 72°F (22°C) at the airport[6], though record extremes have soared to 40.2°C at Heathrow in 2022[2]. The current prediction market assigns a 0% probability to any outcome above 27°C, yet the frontrunner is 27°C at 97%, indicating a sharp divergence between the implied “no” probability and the market’s actual confidence in that specific threshold[1].

Traders should monitor real-time updates from Wunderground, the official resolution source, as well as daily Met Office forecasts which may shift with incoming southerly winds and rising humidity[3][8]. A recent BBC forecast confirms today’s high at 26°C, with Saturday expected to climb to 28°C, suggesting a warming trend that could influence the final reading[3]. Any sudden changes in pressure—currently falling at 1012mb—or wind speed, now at 8 mph, could alter the peak temperature before the settlement window closes at 12:00 UTC on 3 July 2026[3]. Unlike sportsbooks that may offer fixed odds on broader ranges, this market’s granular 97% confidence in 27°C reflects a more precise, data-driven consensus than typical analyst lines.

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

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 PolyGram. 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.

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 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.