Pronóstico: Highest temperature in London on July 3?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 3 July 2026 is currently priced by the Polymarket crowd at 0% for any outcome below 27°C, with the frontrunner being exactly 27°C at 97% probability[1]. This reflects a sharp consensus that the day will not be cool, aligning with recent Met Office and ECMWF ensemble forecasts that project maximum temperatures peaking near 26–27°C[1]. The market, settled on USDC via Polygon using conditional tokens, treats any deviation below this threshold as a near-zero event, effectively pricing in a warm summer day rather than a cold anomaly.

Historically, early July in London City Airport has rarely seen highs below 25°C, with recent data from 2 July 2026 showing a maximum of 26.4°C, recorded at 16:08[10]. The BBC forecast for 3 July also lists a high of 26°C, while the 4 July outlook jumps to 28°C, suggesting a warming trend through the weekend[3]. This pattern mirrors the 2026 monthly average for July, where daily highs range from 71°F to 87°F (21–31°C), making a sub-27°C outcome statistically improbable[7]. The 0% probability assigned to lower ranges is therefore grounded in consistent seasonal behaviour rather than speculative overconfidence.

Traders should monitor the official Met Office daily update for 3 July, which will confirm the maximum temperature and gust data before the settlement window closes at 12:00 UTC on 3 July 2026[9]. Any sudden shift in southerly wind flow or cloud cover could alter the peak, though current conditions show 8 mph southerly winds and 88% humidity, which typically support stable daytime heating[3]. The resolution source, Wunderground, will publish the first data point for the day, and until that occurs, the market remains locked on its current 97% confidence in 27°C[1]. No major weather announcements are expected to disrupt this trajectory, given the absence of extreme forecast warnings in the latest regional bulletins.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

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 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.