Highest temperature in London on July 31?

Platform comparison

Market context

London’s late-July heat is the real-world event behind this market, and the historical frame is straightforward: the capital can get very hot, but the upper end is rare. The Met Office records 37.8°C at Heathrow on 31 July 2020 as one of the standout London-area July extremes, while TORRO and other UK climate summaries show London’s July record cluster is dominated by the 19 July 2022 heatwave, when several London stations reached about 40.0°C to 40.2°C.[2][9][15]

The current 0% Yes pricing is consistent with a market that is effectively betting against an extraordinary late-day spike at London City Airport. For a positive settlement, traders would need the airport station’s highest temperature to land in the market’s specified band, but the more relevant catalyst is whether the day’s peak was already reached by midday or whether a fresh convective surge later in the afternoon could still push readings higher. The Met Office and BBC both note that 2026 has delivered repeated high-temperature episodes in southern England, with London-area maxima around the low- to mid-30s Celsius on recent hot days, which keeps the focus on whether conditions can scale into the upper 30s rather than merely stay warm.[14][17][18]

What matters now is the final Wunderground daily maximum for London City Airport, because that source decides the market. Traders will be watching the day’s official high against the broader London context: recent hot spells have been enough to lift expectations, but the historical benchmark for a truly exceptional outcome remains the 2020 and 2022 extremes rather than ordinary summer warmth.[2][9][14]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Highest temperature in London on July 31? 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.

FAQ

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.

Are political prediction markets legal in my country?

It varies. They sit in legal gray areas in most jurisdictions. Polymarket is geo-blocked from US/UK/EU; some broker frontends have a different geo footprint. Trade only with capital you can afford to lose, and only if you understand the legal status in your jurisdiction.

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.