Highest temperature in London on June 21?

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Active sub-markets

Market context

Polymarket is pricing this as essentially a **0% YES** event, which means traders are treating a June heat spike at London City Airport as highly unlikely and the USDC locked into the relevant Polygon conditional tokens is mostly sitting on the *no* side. The market settles on the highest temperature recorded at the London City Airport Station on 21 June 2026, using Wunderground’s daily history page, and it cannot resolve until the first datapoint for 22 June is published, so late revisions still matter until that cutoff.[1]

The read-through from comparable summer weather patterns is straightforward: London City Airport usually sits in the city’s normal maritime range in mid-June, with the warm season only just underway rather than at peak intensity.[4] Even so, high-end forecasts for the same station can move quickly when a synoptic heat plume builds, and London forecasts have already shown conditions consistent with a warm afternoon, with AccuWeather pointing to about 82°F/61°F and an amber warning for extreme heat around the date.[6] That kind of setup is why a market that looks near-certain can still see small repricing if the forecast stabilises or deteriorates.

A trader watching this contract should focus on the live London City Airport forecast from the Met Office, BBC Weather, and hourly updates that can shift the expected daily maximum in the final hours before settlement.[2][5][7] The key dependency is not the abstract “London weather” headline, but whether the airport station itself prints a temperature in the relevant range before 12:00 UTC on 21 June and whether any later correction appears before the 22 June observation is posted on the resolution source.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on June 21? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket Scam? — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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 Polymarket Scam??

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

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Scam? triggers a quick verification flow that finishes in 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.