Highest temperature in London on June 17?

Platform comparison

Active sub-markets

Market context

On 17 June 2026, the highest temperature recorded at London City Airport will fall into one of several defined ranges, measured in Celsius. The settlement hinges on historical data from Weather Underground's station records, which capture intraday highs rather than daily averages. This specificity matters: London City Airport sits on the Isle of Dogs, where urban heat island effects and proximity to the Thames create microclimatic conditions distinct from central London or suburban stations. The 0% crowd probability suggests either extreme confidence in a particular range or sparse liquidity across all buckets—a common pattern on niche weather markets where traders concentrate positions rather than distribute them evenly.

June temperatures in London typically range from 15–23°C, though extremes have reached 28–30°C during heat waves. The Met Office's 30-year climate normals place mid-June highs around 20–21°C. Recent years have seen greater volatility: June 2022 recorded 32.2°C in parts of southern England, whilst June 2023 remained cooler and wetter. Traders should monitor long-range forecasts from the Met Office and European weather models from late May onwards, as these become more reliable 2–3 weeks ahead. Kalshi's binary structure and Betfair's decimal odds framework would handle this market differently—Kalshi typically resolves on yes/no outcomes, whilst Betfair's exchange format allows traders to back or lay specific temperature bands, offering tighter spreads on consensus ranges.

Methodology

This page compares Highest temperature in London on June 17? 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.

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's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.

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.