Highest temperature in London on May 26?

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Active sub-markets

Market context

On 26 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement relies on historical weather data from Wunderground's station records, finalised by midday UTC. London's late-May climate typically sees highs between 18–22°C, though extremes have occasionally pushed toward 25–27°C in recent decades.

The 0% crowd probability reflects genuine uncertainty about which specific temperature band will resolve, rather than doubt that a measurement will occur. May 2026 forecasting remains inherently speculative at this distance; comparable late-spring days show high volatility. The UK Met Office's seasonal outlooks, published quarterly, will provide the nearest official guidance on whether May 2026 trends warmer or cooler than the 1991–2020 baseline. Historical records from the same station offer calibration: May 2024 saw London highs range from 16–24°C across the month, with individual days varying sharply based on Atlantic weather systems and high-pressure positioning.

Traders should monitor the UK Met Office's long-range forecasts (issued monthly from February 2026 onward) and any El Niño or La Niña updates from the Met Office Hadley Centre, which influence European spring temperatures. The Wunderground source itself requires verification of data availability; occasional station outages or calibration issues have affected historical records. From a regulatory standpoint, this market's accessibility depends on jurisdiction: German traders face GlüStV licensing constraints on prediction markets; US participants remain subject to CFTC oversight of derivatives, though no-KYC access up to $1,500 notional exposure typically permits small-stake weather bets without identity verification. UK residents face no specific prediction-market licensing bar for personal trading at this stake level.

Methodology

We track Highest temperature in London on May 26? 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 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.

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.