Highest temperature in London on May 31?

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Market context

The highest temperature recorded at London City Airport on 31 May 2026 will determine which temperature band resolves this market. London's late May weather typically ranges between 18°C and 24°C, though extremes occasionally push higher. The settlement relies on historical data from Wunderground's London City Airport station, which provides consistent daily maximum temperatures across comparable years.

May temperatures in London have shown considerable year-to-year variation. Between 2015 and 2024, the highest temperatures recorded on 31 May ranged from 16°C to 26°C, with most years clustering between 19°C and 23°C. The 0% crowd probability suggests traders expect temperatures to fall outside the uppermost range bands currently offered, or that the market structure itself may not align with typical late-spring conditions in the capital. Historical precedent indicates late May typically avoids extreme heat, making higher temperature brackets less probable than moderate ranges.

Traders should monitor the Met Office's seasonal forecasts and any emerging climate patterns in spring 2026. The UK's weather in late May depends heavily on Atlantic pressure systems and jet stream positioning, which forecasters typically cannot predict with precision beyond two weeks. Real-time weather models become actionable only in the final week of May, making early trading positions speculative. The 0% probability may reflect uncertainty about which specific temperature band the market offers rather than certainty about the actual weather outcome.

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 31? 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 Election Predictions UK, 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?

Election Predictions UK 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.

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, Election Predictions UK triggers a quick verification flow that finishes in minutes.