Pronóstico: Highest temperature in London on July 5?

Platform comparison

Market context

On 5 July 2026, the highest temperature recorded at London City Airport will determine the outcome of this prediction market, which currently prices the YES option at 0%. This stark valuation suggests the crowd believes the temperature will fall well below the threshold required to trigger a payout, a stance that contrasts with typical July heat patterns in the capital.

Historically, London experiences significant warmth in early July, with the hottest month averaging highs of 22°C (72°F) at London City Airport [7]. The most extreme heat event in recent memory occurred on 19 July 2022, when temperatures soared to 40.2°C across the city, including at Heathrow and St James’s Park [2]. While the current 0% probability implies a cool day, the historical baseline of 28°C highs observed today [1] and the 71–87°F forecast range for July 2026 [9] indicate that a low-temperature outcome is statistically unusual for this season.

Traders should monitor the Met Office’s 7-day forecast updates released on 4 July, as these provide the most reliable precursor data for temperature anomalies [6]. Additionally, watch for any sudden shifts in southerly wind patterns or humidity levels, which currently sit at 88% and could influence heat retention [3]. The contract resolves on-chain via USDC on the Polygon network using conditional tokens, meaning liquidity and price movements will react instantly to these meteorological dependencies rather than abstract speculation [10].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Pronóstico: 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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'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.

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.