Highest temperature in London on June 27?

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Market context

The real-world event this market tracks is the highest temperature recorded at London City Airport on 27 June 2026, measured in degrees Celsius and sourced from Wunderground. Current crowd-implied probability sits at 0% for the “YES” outcome, suggesting traders believe the temperature will fall outside the predefined range, despite recent heatwaves pushing June temperatures across the UK toward record levels.

Historical precedents frame this probability: in 2026, Kew Gardens recorded 26.6°C on 26 June, the hottest day so far this year, while Suffolk hit 37.3°C the same day, marking a provisional new June record for the UK [6][7]. London City Airport typically sees average daily highs above 67°F (24.4°C) during the warm season, which runs from mid-June to early September [2]. These comparable cases suggest that while extreme heat is possible, the 0% probability may reflect a narrow range definition rather than an absence of heat.

Traders should monitor Met Office forecasts for the next 24 hours, as the UK has seen three consecutive days of record June temperatures, indicating sustained atmospheric conditions conducive to further heat [6]. Key catalysts include official weather bulletins, wind patterns from the south, and humidity levels, all of which influence peak temperatures. A recent Sky News report confirms that 26.6°C was recorded in southwest London, reinforcing the trend of elevated temperatures entering late June [7].

From a regulatory standpoint, German GlüStV implications and US CFTC reach affect how such markets are structured and accessible. The “no-KYC up to $1,500” threshold allows traders to participate without identity verification for smaller stakes, enhancing accessibility while remaining within legal frameworks. This specific market’s accessibility hinges on compliance with these overlapping jurisdictions, ensuring that participation remains open yet regulated.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on June 27? 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 PolyGram — 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

Where can I trade this market with the lowest fees?

On PolyGram, 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.

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 PolyGram?

Zero. PolyGram 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, PolyGram triggers a quick verification flow that finishes in minutes.