Pronóstico: Highest temperature in London on July 4?

Platform comparison

Market context

On 4 July 2026, the London City Airport Station will record its highest temperature in degrees Celsius, a real-world event that determines the outcome of this prediction market. Today, Polymarket prices the YES contract at 0%, implying the crowd believes the temperature will fall outside the specified range, likely due to expectations of cooler conditions or a mismatch in the range definition. This stark pricing contrasts with historical data where July is London’s hottest month, averaging highs of 72°F (22.2°C) at this location, with record extremes reaching 40.2°C (104.4°F) during the July 2022 heatwave across the UK[6][2].

Traders should monitor upcoming Met Office forecasts and Wunderground historical updates for the EGLC station, as these are the definitive resolution sources. Recent July 2026 projections for London City Airport suggest daily highs between 71°F and 87°F (21.7°C to 30.6°C), which may align with or exceed the market’s range depending on its exact boundaries[7]. The catalyst for any price shift will be official announcements regarding extreme heat events or corrections to the range definition, as the on-chain mechanics on Polygon using USDC and conditional tokens will only resolve once Wunderground publishes the verified daily maximum[1]. No moralising is needed; the facts show a 0% probability now, but historical volatility in UK summer temperatures means this could change if a heatwave develops.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Pronóstico: Highest temperature in London on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Qué Es, which mirrors the Polymarket order book at 0% fees.

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

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 Qué Es. 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 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 Polymarket Qué Es 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.