Highest temperature in London on June 19?

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Market context

Polymarket is pricing the London City Airport maximum for 19 June through USDC on Polygon, with conditional tokens settling against the Wunderground daily-history record rather than a city-wide average. With the contract sitting at **0% YES**, the market is effectively treating a qualifying temperature band as fully out of the money unless the airport posts a clear same-day extreme before the noon UTC settlement cut-off.

For context, London’s June highs usually sit in the low 20s Celsius, but the current setup is more sensitive to short-lived heat than to the day’s average. Wunderground’s London June history points to a typical monthly high around 21.3°C, while London City Airport’s 2026 records and broader local reporting show that London has already seen warmer spells this month, including a 26.6°C reading at Kew Gardens earlier in the year.[10][6] That matters because this market is resolved by the *highest* reading at a single station on the day, so even a brief afternoon spike can determine the outcome.

The main trader focus is the live weather feed at London City Airport, plus any forecast updates that shift expectations for peak sunshine, wind direction, cloud cover, or maritime cooling. A recent London-and-South-East forecast has called for hot, dry conditions and temperatures into the upper 20s or even around 32°C on 18–19 June, which is the kind of setup that can create a decisive intraday high if it verifies at the airport station.[2] The market cannot resolve until the next day’s first data point is published on the resolution source, so late-session pricing on Polymarket may reflect uncertainty over the final Wunderground print rather than the midday forecast alone.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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

Is this market available outside the US?

Kalshi 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 Kalshi UK?

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

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.