Highest temperature in London on May 25?

Platform comparison

Active sub-markets

Market context

On 25 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The market currently prices all temperature brackets at 0% probability on Polygon, suggesting either illiquidity or that traders are awaiting more concrete seasonal forecasting data before committing USDC to conditional tokens. Settlement hinges on Wunderground's historical weather database for that specific station, which records intraday highs with precision once the day concludes.

London's May temperatures typically cluster between 15°C and 22°C, though the city has recorded highs exceeding 28°C during anomalous warm spells in late spring. The 2022 May heatwave saw temperatures reach 29.5°C on 20 May, whilst more typical years see the month's peak around 20–23°C. These historical ranges provide the baseline against which traders should calibrate their position-taking; the current 0% pricing reflects genuine uncertainty rather than consensus that extreme heat is impossible.

The UK Met Office publishes its monthly outlook in mid-April, with updated forecasts available through May itself. Long-range models from late April 2026 will be the first meaningful catalyst for price movement, particularly if they signal high-pressure systems or Atlantic blocking patterns that could drive temperatures upward. Traders should monitor European weather patterns in early May, as continental air masses frequently determine whether London experiences unseasonably warm conditions or remains within its historical May norm.

Methodology

This page reviews Highest temperature in London on May 25? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at PolyGram — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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.

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 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.