Highest temperature in London on June 9?

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Market context

The London City Airport weather station will record its highest temperature on 9 June 2026, with settlement determined by Wunderground's historical data for that specific date. The resolution window closes at midday UTC, capturing the full diurnal cycle up to that point.

London's June temperatures typically range between 18–23°C, though heat waves can push readings into the high 20s or low 30s. The current 0% crowd probability suggests traders are pricing in either extreme caution or a misalignment with seasonal norms. Historical June records at London City show occasional spikes to 28–30°C during warm spells, but sustained heat above 25°C remains relatively uncommon for early June. The 2022 heatwave pushed temperatures to 40°C in parts of southern England, though London City's readings remained lower due to its location near the Thames and airport microclimatic effects.

Traders should monitor the Met Office's extended forecast from late May onwards, as atmospheric patterns 10–14 days prior typically signal whether high-pressure systems will dominate the UK during early June. North Atlantic jet stream positioning and sea-surface temperatures in the North Atlantic will determine whether continental warm air masses advect northwestward into the British Isles. Any significant warming signals in the 5–10 day forecast window—particularly high-confidence predictions of 25°C or above—would shift market expectations materially from current levels.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

On Champions League Prediction, 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, Champions League Prediction 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.