Highest temperature in London on June 21?

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Active sub-markets

Market context

London City Airport saw a hot 21 June, with the Met Office forecasting a **maximum temperature of 30°C** for the station and showers moving in later in the evening. The market’s settlement source is the daily high recorded at London City Airport Station, so the key question is whether the final official reading lands in the very top end of the day’s range rather than the forecast headline itself.[4][8]

The **0% YES** price implies traders are treating the outcome as highly unlikely, which is hard to reconcile with late-June climatology and the day’s warm-weather setup. London City Airport’s warm season typically runs from mid-June to early September, with average daily highs above 67°F, so a mid- to high-20s Celsius reading is structurally more plausible than a cold June outlier.[3] That said, prediction markets on weather often hinge on the exact station record, and a single cooler marine influence or an earlier peak before cloud and rain can keep the maximum below the obvious round-number thresholds.[1][4]

What matters now is the observed high around the settlement window and whether any late-day weather changes clipped the peak before midday UTC. Wunderground’s station history for EGLC is the resolution source, so traders will be watching for the recorded maximum to be locked in there rather than relying on broader London forecasts or nearby observations.[8] The latest observational feed already shows conditions at the airport well after the event window, but the market only cares about the highest value logged on 21 June at the specified station.[1][2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on June 21? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Champions League Prediction — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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

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 Champions League Prediction?

Zero. Champions League Prediction 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.

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.