Highest temperature in London on July 24?

Platform comparison

Market context

Polymarket prices this London temperature contract at **0% YES** for the current top bracket, so the market is treating a materially hot reading at London City Airport as essentially absent at this point. On Polymarket, traders are buying and selling **USDC**-settled shares on **Polygon**, with the winning conditional token paying out \( \$1 \) if the final Wunderground-reported high falls into the selected range.

For context, London has already seen a recent spell of intense July heat, with the Met Office cited as recording **34°C** on one Monday and forecast highs of **32°C or more** through much of that stretch, with an eventual easing later in the month.[1][5] That matters because this market is not about the calendar-day average but the **single highest temperature** at London City Airport on 24 July, so a brief afternoon spike can move the outcome bracket even if the rest of the day is cooler. July normals in London are far lower, with one climate forecast putting typical daytime highs near **23°C** and nights around **14°C**, which is why the range structure tends to concentrate probability in the warmer-but-not-extreme bins unless a heat event is under way.[2][6]

A trader should watch the **weather forecast cadence**, especially any Met Office updates and short-range model revisions into the afternoon, because the resolution source is a specific station reading rather than a citywide headline figure.[1][5] The market resolves from Wunderground’s London City Airport history page once the day’s data are complete, so the key dependencies are local station observations, not broader London forecasts, and settlement only becomes relevant after the source publishes the final high for the day.[7]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on July 24? 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 PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.