Highest temperature in London on July 5?

Platform comparison

Market context

The real-world event is the daily peak temperature recorded at London City Airport on 5 July 2026, measured in degrees Celsius. Current crowd-implied probability sits at 0% for the “YES” outcome, suggesting the market expects the temperature to fall outside the specified range. This contrasts sharply with sportsbook lines that often price similar weather contracts with non-zero odds, and diverges from analyst consensus which typically assigns a modest probability to extreme heat in early July.

Historical data frames this 0% probability as unusually cautious. July is London’s hottest month, with an average high of 72°F (22°C) at London City Airport, and recent years have seen peaks exceeding 29°C. The July 2022 heatwave, which pushed temperatures above 40°C across the UK, remains a critical benchmark for extreme events, while the July 2025 heatwave also produced notable spikes. These cases suggest that early July can deliver significant warmth, making the 0% implied probability appear disconnected from climatic reality.

Traders should monitor the Met Office’s daily maximum temperature forecasts and Wunderground’s real-time updates for London City Airport, as these are the official resolution sources. A recent Met Office forecast for 5 July 2026 lists a maximum of 29°C, indicating potential alignment with the contract’s range. Additionally, watch for announcements on severe weather clusters or thunderstorm activity, which could suppress temperatures. The National Weather Service has flagged “numerous temperature records” and “clusters of severe thunderstorms” for this period, adding volatility to the outcome.

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Methodology

We track Highest temperature in London on July 5? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Best Prediction Markets UK. 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.

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.

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.