Pronóstico: Highest temperature in London on July 3?

Platform comparison

Market context

The underlying real-world event is straightforward: on 3 July 2026, the highest temperature recorded at London City Airport will be measured in degrees Celsius, with the market resolving to the specific whole-degree range that contains that peak. Despite the user query stating a 0% YES probability for an unspecified outcome, the actual Polymarket contract shows the frontrunner is "27°C" at 97%, with "28°C" trailing at 2%, indicating the crowd is heavily pricing a warm summer day near recent ensemble forecasts of 26–27 °C [1].

Historically, early July in London often sees highs between 24°C and 28°C, and the past two days at London City Airport have already recorded maximums of 26.4°C on 2 July and a forecast high of 26°C for today, 3 July, aligning closely with the current market consensus [3][8]. The Met Office and ECMWF ensemble models consistently project peaks near 26–27 °C for this date, reinforcing why the market assigns such a dominant probability to 27°C rather than treating it as a speculative outlier [1].

Traders should monitor the official Wunderground data release for 3 July, which will settle the market once the first data point for that date is published, and watch for any sudden shifts in the southerly wind flow or humidity levels that could push temperatures toward 28°C [2][3]. While no major weather announcements are scheduled for today, the current high humidity of 88% and falling pressure at 1012mb suggest atmospheric conditions that could sustain or slightly elevate temperatures if the southerly breeze persists through the afternoon [3]. The on-chain mechanics on Polygon, using USDC and conditional tokens, will automatically execute the payout once Wunderground confirms the peak temperature, making data timing the only critical dependency for settlement [2].

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 Argentina, which mirrors the Polymarket order book directly.

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

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'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.

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.