Highest temperature in London on August 1?

Platform comparison

Market context

On 1 August, the key variable is the highest reading logged at London City Airport, not the city-wide headline temperature, so traders need to model a single-station intraday peak rather than a London average. The current crowd price of 0% for a YES position implies the market is effectively dismissing the possibility that the final Wunderground-reported maximum lands in the specified outcome band, which is a useful reminder that venue-specific measurement can diverge from broader forecasts.

For context, London’s August climate is typically mild rather than extreme, with average highs around 19–20°C, but recent years show that brief spikes into the mid-20s can occur when high pressure and southerly flow line up. Polymarket’s own pricing has recently clustered around 25–26°C for this event, with 26°C leading at 59% and 25°C at 31%, which frames the present 0% YES as an outlier versus the listed outcome distribution rather than a consensus weather view. London also set a 2026 local benchmark of 26.6°C at Kew Gardens, showing that the market is being asked to price a warm but not exceptional summer day.

A programmatic trader would watch the forecast run-up, then compare live updates against the settlement source and the market’s revision rule, which allows changes only until the first datapoint for the following date is published. The practical catalyst is not a dramatic announcement but the timing of cloud breaks, sea-breeze suppression, and any late-day warming at Heathrow versus the eastern airport site, because a few tenths of a degree can move the result between adjacent bands. The most recent reporting cited a sunny, mild outlook with a 26°C maximum and 16°C minimum, while the Met Office’s mid-season summary said UK daily maxima were running above average without approaching seasonal record territory.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on August 1? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Bot UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Bot UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Bot UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.