Highest temperature in London on May 29?

Platform comparison

Active sub-markets

Market context

On 29 May 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges. The settlement hinges on data from Wunderground's historical weather records for that specific station, which sits in the Docklands area and typically records slightly warmer readings than central London due to its location and urban heat characteristics. The 0% crowd probability suggests either extreme confidence in a particular outcome or minimal liquidity and trading activity on this specific market.

May temperatures in London historically cluster between 16–22°C, with occasional peaks above 24°C during warm spells. The Met Office's 30-year climate average for late May shows mean highs around 19–20°C, though the record high for May across the UK exceeds 29°C. Comparable prediction markets on weather outcomes across Polymarket, Kalshi, and Betfair show divergent liquidity patterns: Polymarket typically offers decimal odds with lower fees (2%) but faces KYC restrictions in several jurisdictions, whilst Kalshi operates under CFTC oversight with stricter US-focused settlement criteria, and Betfair's exchange model allows peer-to-peer pricing that can reflect sharper probability shifts when new forecasts emerge.

Traders should monitor the UK Met Office's extended outlook in late May, which will clarify whether high-pressure systems or Atlantic weather fronts dominate the period. Temperature forecasts become reliable only 10–14 days ahead, meaning meaningful probability shifts will likely occur in the final fortnight before settlement. The choice of London City Airport as the resolution source matters: this station's readings can differ by 1–2°C from other London locations depending on wind patterns and cloud cover.

Methodology

This page compares Highest temperature in London on May 29? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to Polymarket Alternative, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Alternative, 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?

Polymarket Alternative 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.

What does it cost to trade on Polymarket Alternative?

Zero. Polymarket Alternative 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.