Highest temperature in London on June 3?

Platform comparison

Active sub-markets

Market context

On 3 June 2026, the highest temperature recorded at London City Airport will determine which range this market settles into. The settlement mechanism relies on historical data from Weather Underground, with the resolution timestamp set for 12:00 UTC on that date. Traders should note that different platforms handle temperature markets with varying precision: Kalshi typically offers tighter band definitions and clearer settlement criteria, whilst Betfair's decimal odds format can obscure the actual probability distribution across ranges. Polymarket's implied probability display differs structurally from Smarkets' fractional odds presentation, affecting how traders compare conviction across books.

London's June temperatures have historically ranged between 18°C and 28°C, with the long-term average high around 21°C. The 0% crowd probability currently assigned suggests either extreme confidence in a specific outcome or insufficient liquidity across all ranges. Comparable June weather markets on these platforms have shown significant divergence when atmospheric patterns shift unexpectedly; the Met Office's seasonal outlooks and North Atlantic Oscillation indices provide early signals for anomalous warmth.

Traders should monitor the European summer pattern forecast from mid-May onwards, particularly high-pressure systems tracking across the Atlantic. The UK Health Security Agency typically issues heat-health alerts when temperatures exceed 30°C, which would represent a material tail event. Cross-platform comparison reveals that Kalshi's KYC requirements and US-focused user base sometimes create pricing inefficiencies versus Betfair's international liquidity, particularly for UK-specific weather events.

Methodology

This page compares Highest temperature in London on June 3? 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 Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Kalshi Alternative UK routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative 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?

Kalshi Alternative 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.

What does it cost to trade on Kalshi Alternative UK?

Zero. Kalshi Alternative UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Kalshi Alternative UK 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.