Pronóstico: Highest temperature in London on June 28?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 28 June 2026 will determine the outcome of this prediction market, with the current crowd-implied probability for a "YES" result sitting at 0%. This reflects the market’s assessment that the temperature will fall outside the specific range being traded, likely due to the day’s forecasted conditions of 26°C high and 13°C low, as noted by BBC Weather[2].

Historically, London’s late June temperatures have averaged above 67°F (19.4°C) during the warm season, which runs from mid-June to early September[4]. However, this year has seen record-breaking heat, with the UK surpassing its June temperature record of 35.6°C to reach 36.1°C just days prior[9]. Such extremes suggest that while high temperatures are possible, the specific range in this contract may still be unlikely, given the current 0% probability.

Traders should monitor the Met Office’s ongoing heat warnings and any updates on temperature thresholds, especially as the red extreme heat warning was extended recently due to temperatures reaching 35.1°C in London[7]. With the settlement window closing at 12:00 UTC on 28 June 2026, the on-chain mechanics—USDC on Polygon using conditional tokens—will lock in the final resolution based on Wunderground’s official data[1]. The key catalyst is whether the day’s actual peak exceeds the contract’s upper bound, a factor heavily influenced by the current heatwave trend.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Pronóstico: Highest temperature in London on June 28? 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 Argentina, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Argentina. 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.

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.