Highest temperature in London on June 4?

Platform comparison

Active sub-markets

Market context

On 4 June 2026, the highest temperature recorded at London City Airport Station will determine which range this market resolves to. The settlement window closes at 12:00 UTC on that date, with Wunderground's historical weather data serving as the authoritative source. London's June temperatures typically range between 15–22°C, though heat waves can push readings into the mid-to-high 20s. The 0% crowd probability suggests traders currently expect no outcome within the lowest temperature bracket offered, though the specific range thresholds are not yet visible in the market structure.

Historical June weather patterns at London City Airport show variability tied to Atlantic pressure systems and occasional continental warm air advection. The Met Office records indicate that June averages around 19°C for daily highs, with extremes rarely exceeding 28°C at this location. The current nil probability may reflect either an unusually narrow lowest bracket or trader consensus that early June conditions will remain moderate. Comparable markets on UK airport temperatures have typically seen clustering around the 18–22°C bands, particularly when settlement windows fall early in the month before summer heat intensifies.

Traders should monitor the Met Office's extended forecast from late May onwards, as the North Atlantic Oscillation and jet stream positioning in the fortnight before 4 June will signal whether high-pressure systems establish over the UK. The UK Health Security Agency issues heat-health alerts when temperatures exceed regional thresholds, though June alerts remain uncommon. Any significant weather pattern shifts—such as a Scandinavian high or southwesterly flow from the Iberian Peninsula—would alter the probability distribution materially. Regulatory access to this market depends on jurisdiction: EU traders face German GlüStV compliance requirements, whilst US persons fall under CFTC derivatives oversight. Non-KYC trading up to $1,500 notional exposure typically applies to prediction markets on non-financial events, though individual platform terms vary.

Methodology

We track Highest temperature in London on June 4? 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

Where can I trade this market with the lowest fees?

On Polymarket Legal 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.

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 Legal UK?

Zero. Polymarket Legal 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 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.

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.