Highest temperature in London on May 25?

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Active sub-markets

Market context

The market concerns the highest temperature recorded at London City Airport on 25 May 2026, with settlement based on historical weather data from Weather Underground. The 0% crowd probability suggests traders are either uncertain about the specific temperature range or awaiting clarity on which bands the market offers.

London's May temperatures typically range between 15–22°C, with historical highs occasionally reaching 25–28°C during warm spells. The Met Office's long-term climate records show that temperatures exceeding 30°C in May are rare but not unprecedented; the UK experienced a notably warm May in 2022, when several regions recorded highs above 25°C. Traders should reference the UK Climate Projections and recent May weather patterns from the past five years to calibrate expectations for what constitutes an outlier outcome versus a typical spring day.

The primary catalyst for this market is the approach of late May 2026 itself, as real-time weather forecasts become actionable only in the days immediately preceding the settlement date. Medium-range forecasts (10–14 days out) carry substantial uncertainty; the Met Office typically issues reliable five-day outlooks by late May. Traders monitoring the Atlantic pressure systems and jet stream positioning in the weeks before 25 May will gain early signals about whether continental high-pressure systems might drive anomalously warm conditions into the UK. Current seasonal models and any official Met Office long-range updates closer to the date will be the key information sources for adjusting positions.

Methodology

This page tracks Highest temperature in London on May 25? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. PolyGram routes every trade through to Polymarket — at 0% fees.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

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.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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.

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.