Highest temperature in London on July 4?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 4 July 2026 will determine the outcome of this prediction market, with the current crowd-implied probability for a 28°C threshold sitting at 0% YES. On Polymarket, this contract trades on the Polygon network using USDC, where conditional tokens reflect the market’s near-certainty that temperatures will remain below that mark. The settlement window closes at 12:00 UTC on 4 July 2026, and resolution data comes from Wunderground’s official daily record for EGLC.

Historically, July is London’s hottest month, with London City Airport averaging a high of 72°F (22.2°C) [2]. While the 2022 heatwave saw London reach 40.2°C at Heathrow and St James’s Park [7], such extremes are rare at EGLC, which typically records lower peaks due to its urban, coastal location. The Met Office notes a maximum feels-like temperature of 25°C for recent July days at this station [4], reinforcing why the market prices 28°C as highly improbable.

Traders should monitor the Met Office’s daily forecasts and Wunderground’s real-time updates, as sudden shifts in southerly flow or humidity could alter peak temperatures. Recent forecasts for July 2026 suggest daily highs between 71°F and 87°F (21.7°C–30.6°C) at EGLC [6], yet thin volume and two days to resolution make this market volatile [10]. No major weather announcements are scheduled, but the National Weather Service’s hourly METAR data for EGLC remains a key dependency for accurate tracking [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 Polymarket Legit?, which mirrors the Polymarket order book directly.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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 Polymarket Legit? 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.