Highest temperature in London on June 19?

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Market context

London City Airport’s peak temperature on 19 June is the settlement point here, and the market is pricing an extreme **underdog** outcome with just **0% YES** implied probability. That makes anything in the higher temperature bands the consensus favourite by default, while the value question is whether the day finishes warmer than the live crowd expects or stays pinned to a more ordinary early-summer range. Recent observed and forecast data around the airport have already shown a very different picture from a hot-day breakout: BBC Weather had a forecast high of **25°C** for Friday with light south-south-westerly winds and no expected precipitation, while the Met Office was showing a more restrained **23°C** maximum and **14°C** minimum for the same location. [2][6]

Historically, London City Airport in mid-June is usually a mild, variable setup rather than an outlier heat event. Weatherspark puts the warm season in London City Airport at roughly late June through early September, with average highs above 67°F, which is about **19°C**, so the market’s 0% YES price reads as a strong sceptical view rather than a denial that warmth is possible. [5] In handicapper terms, the favourite is the mid-20s band, but the contrarian angle is that airport readings can still undershoot headline city forecasts if cloud, onshore flow, or showers suppress the afternoon peak. The current setup therefore leaves value only if a trader believes the consensus is underestimating the day’s ceiling rather than the likely central tendency. [2][3][6]

The main catalysts are intraday forecast revisions and the actual station observations feeding the Wunderground history page used for settlement, with the key watchpoint being whether the airport reaches its maximum before the midday settlement cut-off. The Weather Network’s live feed has already shown a mixed picture for London City Airport, including rain and cloud earlier in the day, while the NWS METAR feed confirms the station is reporting in real time at EGLC. [3][4][9] If late-morning sunshine breaks through and winds stay light, the market’s underdog low-probability heat bands can re-rate quickly; if cloud and showers linger, the favourite remains the cooler, lower range.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on June 19? 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 Who Will Win — 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

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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?

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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.