Highest temperature in London on June 23?

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Active sub-markets

Market context

The underlying event is the peak daily temperature recorded at London City Airport on 23 June 2026, with markets betting overwhelmingly on a sweltering outcome exceeding typical summer norms. Current odds imply a 99% probability that the heat will reach a specific high threshold, reflecting intense confidence in an extreme weather day driven by prevailing southerly flows and abundant sunshine.

Historically, late June in London rarely breaches 35°C, yet recent years have seen record-breaking spikes that challenge this baseline. In 2022, temperatures soared to 40°C, shattering the previous June maximum, while 2018 also delivered near-record highs of 94°F under similar atmospheric conditions[7][8]. These comparable cases suggest that while 99% confidence is aggressive, the climate trend towards more frequent heatwaves makes such extremes increasingly plausible rather than anomalous.

Traders should monitor scheduled meteorological bulletins and any sudden shifts in wind direction that could disrupt the heat dome. The market is leaning heavily on the continuation of the current high-pressure system, with no immediate forecasts predicting precipitation or cooling breezes for the settlement window[2][6]. Recent climate disclosures from the Met Office confirm that June 2026 is tracking as one of the hottest starts to summer in decades, reinforcing the bullish temperature outlook[6]. Watch for real-time updates from Wunderground, the designated resolution source, as they publish the first data point for the day[1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for Highest temperature in London on June 23? plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

FAQ

Where can I trade this market with the lowest fees?

On Election Predictions UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Election Predictions UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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.

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.