Highest temperature in London on June 24?

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Active sub-markets

Market context

London City Airport is currently facing a red warning for extreme heat, with conditions staying warm and muggy under clear skies as southerly winds push temperatures toward a daily high of 28°C [3]. The crowd-implied probability sits at 76% YES for the market, suggesting a strong consensus that the temperature will breach the lower threshold of the target range, yet the value spot likely lies with the contrarian angle that 36°C is an outlier for early June [1]. Historical climatological norms indicate the warm season only begins mid-June, with average daily highs just above 67°F, making a 36°C peak a significant deviation that would break the existing June maximum record by 2–3°C [5][8].

Traders must watch the Met Office’s headline forecast of 39°C for Thursday, which could drive advection of warmer air if cloud cover clears rapidly, though current model consensus suggests substantial deviation is unlikely before resolution [2][10]. The primary dependency is the persistence of the current high-pressure system and the lack of unforecasted cloud clearance, as the prevailing southerly flow and 88% humidity currently stabilise the atmosphere against extreme spikes [3]. While the Met Office has flagged 39°C as a potential maximum, the ensemble models show tight clustering around climatological norms, implying the market’s 76% confidence may be slightly overvalued against the risk of a cooler, muggy day [2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 24? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

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 it cost to trade on Who Will Win?

Zero. Who Will Win routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.