Highest temperature in London on May 23?

Platform comparison

Active sub-markets

Market context

The market concerns the highest temperature recorded at London City Airport on 23 May 2026, with settlement based on historical weather data from Weather Underground. The 0% implied probability suggests traders are either uncertain about the resolution mechanism or treating this as a calibration exercise rather than a genuine weather forecast.

London's May temperatures typically range between 12°C and 20°C, though extremes occasionally exceed these bounds. The Met Office's 30-year climate averages show mean daily highs around 18–19°C for late May, with record highs in the low-to-mid 20s Celsius. Historical data from the City Airport station itself provides the most relevant baseline: traders should examine May temperature distributions from prior years on the Weather Underground archive to establish realistic outcome ranges. The 0% probability may reflect confusion about whether the market is asking for a specific threshold or a range-based resolution, rather than genuine scepticism about temperature occurrence.

Traders should monitor the Met Office's long-range forecasts as May 2026 approaches, though predictive skill at that horizon remains limited. The resolution depends entirely on the automated recording at London City Airport and Weather Underground's data finalisation process, creating minimal uncertainty beyond standard meteorological variation. Recent spring seasons in the UK have shown increased volatility, with some years producing notably warmer late-May conditions than historical norms, though systematic climate trends remain modest at this location.

Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for Highest temperature in London on May 23? plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

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 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.

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.