Highest temperature in London on June 27?

Platform comparison

Active sub-markets

Market context

The underlying real-world event is the peak daytime temperature recorded at London City Airport on 27 June 2026, with current models suggesting a record-breaking heatwave is already disrupting UK airports and pushing temperatures toward 37°C at nearby Heathrow[6][8]. While the specific market you referenced shows a 0% probability for a "YES" outcome, this likely stems from a misunderstanding of the resolution mechanics, as the frontrunner for the 31°C range currently holds 46% of the market volume, with 32°C trailing at 37%[1]. Historical comparables from earlier in June, such as the 17°C maximum on 6 June under unsettled conditions, frame the current volatility, while the 21°C low temperature forecast for 27 June suggests a significant diurnal swing typical of extreme heat events[2][3].

Traders should monitor the Met Office’s provisional record announcements and the timing of thunderstorms, which are already causing flight delays and could abruptly lower peak temperatures if they arrive before midday[6][10]. The resolution source is Wunderground data for London City Airport, and any discrepancy between Heathrow’s 37.8°C reading and the airport station’s actuals will determine the final outcome[8]. Regulatory accessibility for this market is shaped by the German GlüStV, which may restrict participation for German residents, and the US CFTC, which maintains reach over unregistered prediction platforms; however, the "no-KYC up to $1,500" threshold allows traders to access this specific market without identity verification, provided they stay within that limit and are not in a jurisdiction with explicit bans[5]. This structure ensures broad accessibility while navigating complex international compliance frameworks without requiring legal counsel.

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 PolyGram, which mirrors the Polymarket order book directly.

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

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 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.

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, PolyGram triggers a quick verification flow that finishes in 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.