Highest temperature in London on June 13?

Platform comparison

Active sub-markets

Market context

On 13 June 2026, the highest temperature recorded at London City Airport will determine which range this market settles into. The resolution hinges on a single data point from Wunderground's historical weather archive for that specific station, making this a straightforward factual event with no ambiguity once the day passes. The 0% crowd probability suggests traders are either not yet pricing this market or treating it as a placeholder pending range options.

London's June temperatures typically peak between 20–24°C, though the city has recorded highs above 30°C during heatwaves. The Met Office's long-term climate data shows June averages around 21°C, with extreme outliers occurring roughly once per decade. Comparable markets on Polymarket and Kalshi have historically seen temperature ranges priced according to seasonal norms rather than tail-risk scenarios, though Kalshi's decimal-odds format can obscure whether low probabilities reflect genuine uncertainty or thin liquidity. Betfair's exchange model allows sharper price discovery on niche weather events, whilst Smarkets' fee structure (4% taker) incentivises tighter spreads on settled outcomes.

Traders should monitor the UK Met Office's extended forecast from early June, which typically gains reliability within a 10-day window. Any Atlantic weather systems or high-pressure systems tracking towards the British Isles in mid-June will shift expectations materially. The settlement window closes at midday on 13 June, giving traders a narrow window to adjust positions based on morning forecasts. Cross-platform comparison reveals that Kalshi's regulated US structure may delay UK settlement slightly compared to Betfair's real-time updates, a material consideration for same-day weather events.

Methodology

This page compares Highest temperature in London on June 13? 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

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 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.

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, 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.