Highest temperature in London on June 17?

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Active sub-markets

Market context

On 17 June 2026, the highest temperature recorded at London City Airport Station will fall into one of several defined ranges. The settlement will draw from Wunderground's historical weather database, which logs daily maxima for that specific monitoring location in the Docklands. The 0% crowd probability suggests traders currently expect the market to resolve outside the YES range specified in the full terms, though the exact threshold boundaries determine whether any outcome qualifies.

London's June temperatures have historically ranged between 18°C and 28°C, with extremes occasionally breaching 30°C during heat waves. The 2022 heatwave saw London exceed 40°C in early July, and June 2019 recorded 32°C at Heathrow. City Airport, positioned near the Thames estuary, typically runs 1–2°C cooler than central London due to maritime influence. Comparable June days over the past decade suggest a modal outcome between 20°C and 25°C, which would align with the crowd's current scepticism towards higher ranges if those are what the market's YES criteria require.

Traders should monitor the Met Office's seasonal outlook and any Atlantic weather systems forecast for mid-June 2026. High-pressure systems moving north from the continent can drive temperatures upward; conversely, Atlantic low-pressure troughs bring cooler, wetter conditions. The settlement window closes at 12:00 UTC on 17 June, meaning Wunderground's recorded maximum for that calendar day becomes final. No interim announcements or forecaster revisions alter the outcome once the day concludes and historical data is published.

Methodology

We track Highest temperature in London on June 17? 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

Is this market available outside the US?

Polymarket Legal 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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

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