Highest temperature in London on August 17?

Platform comparison

Market context

The market seeks to establish the highest temperature recorded at London City Airport on 17 August 2026, measured in degrees Celsius via Weather Underground's Daily Observations table. The settlement window closes at midday on that date, meaning the resolution source captures the full morning and early afternoon period but excludes any late-afternoon or evening peaks that might occur after noon.

London's August temperatures have historically ranged between 20°C and 28°C, with extremes occasionally reaching into the low 30s during heatwaves. The 0% crowd probability suggests traders are either uncertain about the specific threshold ranges offered or expect a relatively moderate day. August 2026 falls within standard UK summer patterns, though climate variability means both cooler-than-average and warmer-than-average outcomes remain plausible. Historical data from the Met Office shows that London experiences measurable year-to-year variation in peak August temperatures, with some years producing sustained heat and others delivering more temperate conditions.

Traders should monitor long-range weather forecasts released in the weeks preceding mid-August 2026, particularly from the UK Met Office and European weather services, which typically issue reliable 10-to-14-day outlooks by early August. Atmospheric pressure systems, jet stream positioning, and any continental heat drifting northward from mainland Europe will be the primary drivers of temperature outcomes. The specific resolution source—Weather Underground's Daily Observations at London City Airport rather than broader London averages—means local microclimatic factors at that station location will determine settlement, potentially differing slightly from readings elsewhere in the capital.

Methodology

This page tracks Highest temperature in London on August 17? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. For users geo-blocked from Polymarket directly, brokers like Trump Prediction provide a 0%-fee route into the same order book.

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

How accurate are political prediction markets?

Historically more accurate than polls. Polymarket's Brier score on US 2024 elections was ~0.11 — better than 538 (~0.14) and every mainstream poll. Markets aggregate information with real skin in the game.

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.

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.