Highest temperature in London on July 31?

Platform comparison

Market context

The event is the highest temperature recorded at London City Airport on 31 July, measured in Celsius and locked in by the Wunderground history page for that station. The market’s current 0% YES price implies the crowd sees the relevant range as effectively out of reach, but that should be read against London’s normal late-July distribution, where average daily highs are around 21–23°C and even warmer spells usually need a broader heatwave set-up to push into the high 20s or low 30s.[1][11]

Historically, London’s real tail risk sits in heatwave years rather than ordinary summer weather. The Met Office notes 31 July 2020 reached 37.8°C at Heathrow, while 19 July 2022 saw 40.2°C at St James’s Park, Heathrow, Kew, and Northolt, showing that London can briefly print extreme maxima when hot continental air locks in over the south-east.[3][4][9][13] By contrast, more typical July highs stay much lower, so a sub-30°C outcome is materially more common than a record-chasing spike. That makes very low probabilities on the hottest brackets easier to understand, but it also means a single forecast error or localised urban heating effect can move the final band if the day turns anomalously warm.[11][13]

For catalysts, traders should watch Met Office short-range updates, especially whether London remains under an active heatwave, and whether BBC or other UK outlets flag temperatures in the low 30s for south-east England before the relevant airport reading is taken.[5][16] London City Airport is a coastal-adjacent, urban station, so cloud cover, sea-breeze influence, and timing of the day’s peak can all matter more than broad national headlines. On accessibility, the market sits inside a regulated prediction-market framework where German GlüStV rules may restrict access for users in Germany, US CFTC reach is relevant if a platform is offering derivatives-like event contracts to US persons, and “no-KYC up to $1,500” generally means smaller-volume participation may be available without full identity verification, but only within the platform’s own thresholds and any jurisdictional limits.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This overview of Highest temperature in London on July 31? reviews the four comparable platforms from a regulatory perspective: which is accessible in your jurisdiction, where KYC kicks in, how the platform is classified by your country of residence. Live probability is the Polymarket mid; comparison columns show regulatory status, KYC thresholds and settlement options for each platform.

Resolution & payout

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FAQ

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Not for lifetime trading volume under $1,500. Above that threshold, a quick KYC flow kicks in — ID, selfie, approximately 5-10 minutes. The threshold matches FATF travel standards for unregulated crypto platforms.

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You're responsible for documenting your trades. Is Kalshi Legal in California exports a full transaction history (CSV/PDF) for tax reporting. In an audit you'll need to present these documents.

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Legally unclear in most jurisdictions. Some interpretations classify them as wagering (gambling regulation applies), others as derivatives (financial regulation applies). There's no global precedent specifically for on-chain prediction markets.

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No platform-side cap. You can withdraw any amount provided KYC is complete. SEPA bank withdrawals over €15,000 trigger additional anti-money-laundering checks (statutory obligation for all platforms).