Highest temperature in London on June 22?

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Market context

Polymarket’s contract on the **highest temperature at London City Airport on 22 June** is pricing at **0% YES** today, with settlement driven by the daily maximum reported in Celsius on Wunderground rather than by any broader London reading. On-chain, the bet is held and traded as **USDC** on **Polygon**, with the market resolving through the conditional-token structure once the final airport observation is known.

For context, London City Airport can easily sit in the teens in the morning and then lift sharply if sunshine, slack winds and a warm airmass line up, but the airport’s coastal-ish eastern location also makes it vulnerable to sea-breeze limits and showers that cap the day’s peak. Wunderground’s own London City Airport page currently shows a **13°C observation** with the day forecast reaching **28°C**, while BBC Weather shows a much wider spread, with **28°C today** and higher maxima later in the week, which is the sort of set-up that can leave a low-probability market underpriced if traders focus too much on the morning read-through.[2][8]

The main catalysts are the **hour-by-hour forecast updates**, any late changes in cloud cover, wind direction or shower timing, and the fact that the settlement window ends at **12:00 UTC**, so only the reading captured by then matters. For a trader, the practical dependency is simple: if the airport stays under a cap of cloud or an onshore flow, the realised high can lag the headline forecast; if the Met Office or BBC trims the rain risk and temperatures accelerate into early afternoon, the conditional token may reprice quickly before expiry.[2][6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket UK, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket 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 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 does it cost to trade on Polymarket UK?

Zero. Polymarket 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.