Highest temperature in London on June 1?

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Active sub-markets

Market context

London's weather on 1 June 2026 will be recorded at City Airport, with the market seeking which temperature band will capture that day's high. Early June typically sits at the threshold between spring and summer conditions across southeast England, with historical averages around 20–22°C, though the range between cool and warm days can span 10°C or more depending on prevailing air masses.

June in London has produced highs exceeding 28°C in roughly one year per decade over recent decades, most notably the 2022 heatwave season which saw multiple days above 30°C. Conversely, cooler Junes with highs stuck in the mid-teens remain plausible when Atlantic low-pressure systems dominate. The 0% crowd probability suggests traders are pricing in either extreme confidence in a specific narrow band or genuine uncertainty about which outcome to back at current odds.

The Met Office issues extended outlooks roughly two weeks ahead, with more reliable forecasts emerging five to seven days before the date. Traders should monitor late May weather patterns—particularly whether high-pressure systems establish over the continent or Atlantic systems push in—as these determine whether June 1st experiences continental warmth or maritime coolness. Solar activity and sea-surface temperatures in the North Atlantic will influence the jet stream positioning by that date, making late-May forecasting updates the key catalyst for probability shifts.

Methodology

We track Highest temperature in London on June 1? 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Prediction Today, 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Prediction Today 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.