Highest temperature in London on August 19?

Platform comparison

Market context

On 19 August 2026, London City Airport will record its highest temperature for that calendar date. The market resolves to whichever temperature band contains the peak reading from the Daily Observations table on Weather Underground, using data specifically from the London City Airport Station rather than summary figures. The 0% crowd probability suggests traders currently expect no outcome within the lowest temperature bracket offered, or uncertainty about which range will ultimately contain the day's maximum.

August temperatures in London have historically ranged between 20°C and 28°C on the 19th over recent decades, with occasional excursions beyond these bounds during heat waves. The Met Office records show that whilst 19 August is typically a warm summer day in the capital, extreme heat events remain statistically infrequent. Comparable August dates in 2022 and 2023 saw highs in the mid-20s Celsius, providing a baseline against which traders might calibrate expectations for 2026. The specific reliance on Weather Underground's Daily Observations table—rather than rounded summary highs—introduces precision that may shift outcomes between adjacent temperature bands.

Traders should monitor long-range weather forecasts released in early August 2026, particularly any alerts from the Met Office regarding heat waves or unsettled conditions across south-east England. Atmospheric patterns in late summer can shift rapidly; high-pressure systems tracking over the UK would push temperatures upward, whilst Atlantic weather systems could suppress them. The settlement window closes at midday on 19 August, meaning final forecasts from the UK's meteorological services in the days immediately preceding will carry material weight for market positioning.

Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for Highest temperature in London on August 19? plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

Resolution & payout

For political markets the resolution source is decisive. Polymarket defines a concrete source per contract (e.g. AP, Reuters, official electoral commission) and uses the UMA Optimistic Oracle as the on-chain dispute mechanism. With a clearly defined outcome the USDC payout lands within minutes of the final confirmation.

UK Frequently Asked Questions

What resolution source is used for elections?

Polymarket defines the source per contract — usually Associated Press (AP Race Call), Reuters or the official electoral commission. The source is stated in contract details before the market opens.

Can prediction markets influence election outcomes?

Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.

How fast do political markets react to news?

High-liquidity markets move within seconds to minutes. A Trump tweet on the economy can shift the "Trump 2024" market 2-5 points before mainstream media has written anything.

Why do Polymarket and Kalshi differ on elections?

Kalshi must follow CFTC compliance — strict definitions, clear resolution sources, US citizens only with KYC. Polymarket operates globally without CFTC oversight — deeper liquidity, but also higher regulatory risk.

Are UK election prediction markets available from the UK?

Yes. Betfair Exchange and Smarkets offer UKGC-regulated UK election markets (seat counts, party share, constituency results). Polymarket also lists UK election contracts with deeper global liquidity. Betfair winnings are typically tax-free for UK individuals; Polymarket profits are subject to HMRC CGT.