Highest temperature in London on June 9?

Platform comparison

Active sub-markets

Market context

On 9 June 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement mechanism relies on historical weather data from Wunderground, capturing the peak daily temperature in Celsius at this specific monitoring station. The 0% crowd probability suggests traders currently perceive no meaningful chance of an extreme heat outcome, though the market structure permits resolution across multiple temperature bands.

London's June temperatures typically range between 18–23°C, with historical highs occasionally reaching 28–30°C during warm spells. The Met Office records show that June 2022 saw London peak at 32.2°C, whilst June 2019 reached 34.1°C—both exceptional but not unprecedented events. The current zero probability likely reflects baseline seasonal expectations rather than forecasting confidence; comparable weather markets on Polymarket show similar clustering at lower ranges when settlement dates lie several months ahead and no extreme weather pattern is currently developing.

From a regulatory standpoint, this market operates under different compliance frameworks depending on trader location. The German GlüStV (gambling licensing statute) treats prediction markets as wagering products requiring operator licensing; UK-domiciled traders face no equivalent statutory barrier for financial prediction markets. US CFTC jurisdiction applies only to derivatives on regulated commodities or indices, leaving weather prediction markets in a grey zone for American participants. The "no-KYC up to $1,500" threshold common on some platforms means casual traders can access this market without identity verification below that stake level, though operators may impose stricter requirements based on their own licensing jurisdiction.

Methodology

We track Highest temperature in London on June 9? 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

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 Polymarket Tax 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.

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 Polymarket Tax UK?

Zero. Polymarket Tax 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 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.