Highest temperature in London on June 21?

Platform comparison

Active sub-markets

Market context

London City Airport’s highest reading on 21 June will be driven by the day’s actual afternoon warmth, with the market set to resolve only after the final data for that date is published on the Wunderground history page for EGLC. The current crowd price of **0% YES** implies traders see an outcome outside the named range as overwhelmingly unlikely, but it is worth reading that against the station-specific nature of the contract: the settle­ment depends on the single highest observed Celsius reading, not a broader London forecast.

Historically, this kind of weather market tends to track late-june London climatology more than any single headline forecast. London City Airport usually sits in the warm season by now, when daily highs are commonly in the high teens to low twenties Celsius, but genuinely hot spikes still occur and can push the day’s maximum into the upper twenties. The comparable crowd view in the next-day Polymarket market already clusters around **28°C–29°C** as the frontrunner, which is consistent with traders leaning on a warm-summer pattern rather than assuming an extreme heat event.[1][4]

The key catalyst is the short-range forecast for east London, especially any Met Office or BBC Weather shift in the expected afternoon high for London City Airport, because even a one- or two-degree revision can move the likely settlement band materially.[3][6] For a June 21 settlement, the market is also sensitive to whether the day stays sunny through the late afternoon or loses heating to cloud, rain, or a sea-breeze effect; those are the main dependencies traders will be watching rather than longer-range seasonal averages.[3][6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Highest temperature in London on June 21? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. Trump Prediction routes every trade through to Polymarket — at 0% fees.

Resolution & payout

For political markets the resolution source is decisive. Polymarket defines a concrete source per contract (e.g. AP, Reuters, official electoral commission) and uses the UMA Optimistic Oracle as the on-chain dispute mechanism. With a clearly defined outcome the USDC payout lands within minutes of the final confirmation.

FAQ

Where can I trade this market with the lowest fees?

On Trump Prediction, 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?

Trump Prediction 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.