Highest temperature in London on June 12?

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Active sub-markets

Market context

The settlement of this contract hinges on the maximum temperature recorded at London City Airport on 12 June 2026. The Met Office's historical data shows that mid-June temperatures in central London typically range between 18°C and 23°C, with extremes occasionally reaching 25–27°C during warm spells. The 0% crowd-implied probability suggests traders are pricing in either a specific temperature threshold that historical patterns make unlikely, or uncertainty about which range bands are available in the full contract structure. Comparable June days at the same station over the past decade provide the most reliable baseline: the median high has settled around 20–21°C, with only one in four Junes producing readings above 24°C.

The UK's seasonal weather patterns and Atlantic pressure systems will be the primary drivers. Early June 2026 forecasting remains speculative at present, but the Met Office's long-range outlooks typically become actionable only within two weeks of the settlement date. Traders should monitor the European Centre for Medium-Range Weather Forecasts (ECMWF) and GFS model consensus as mid-May approaches, particularly any signals of high-pressure systems or warm continental air masses moving northward. Recent years have shown increasing frequency of June heat events, though London City Airport's location near the Thames means maritime influence often moderates peak temperatures compared to inland sites. The specific resolution source—Wunderground's historical data feed for EGLC station—is reliable but occasionally subject to minor delays in updating.

Methodology

We track Highest temperature in London on June 12? 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

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 Best Prediction Markets 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?

Best Prediction Markets 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 Best Prediction Markets UK?

Zero. Best Prediction Markets UK 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, Best Prediction Markets UK triggers a quick verification flow that finishes in minutes.