Highest temperature in London on June 19?

Platform comparison

Active sub-markets

Market context

The event is the **highest temperature recorded at London City Airport on 19 June**, measured during the day and later matched to the market’s Celsius range. London is already in a warm spell: BBC Weather showed London City Airport at **13°C at 10:31 BST on 19 June**, while the Met Office forecast for the same station pointed to a **maximum temperature of 31°C** and a low of 17°C, which is the sort of setup that can drive a wide intraday spread between early-morning readings and the eventual peak.[2][5]

For a trader reading the current **0% YES** price, the key historical lens is simple: London City Airport’s June climate usually sits in the warm-season band rather than at extremes, with WeatherSpark describing the warm season as running from **16 June to 8 September** and average daily highs above **67°F**.[4] In recent comparable market snapshots on Polymarket, outcomes have often concentrated in a single temperature bucket once the day’s thermal pattern is clear, which means a zero price can be less informative than the implied distribution of likely highs and the station-specific forecast path.[1]

Programmatically, this is best handled as a timed data feed problem rather than a headline trade. A bot or conditional-order workflow would poll the forecast and observation stream for **London City Airport (EGLC)**, watch for revised maximum-temperature guidance from official or near-real-time sources, and compare those inputs with the Wunderground history page used for settlement; once the settlement window closes at **12:00 UTC**, only the recorded maximum through the market’s rules matters.[3][5][7] The practical catalyst is therefore the day’s temperature trajectory, not scheduled events, with the most useful updates coming from forecast revisions, live observations, and any heat-warning messaging that shifts expectations for the afternoon peak.[2][5]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 19? 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

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

Where can I trade this market with the lowest fees?

On Polymarket Review 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?

Polymarket Review 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.

What does it cost to trade on Polymarket Review UK?

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