Pronóstico: Highest temperature in London on July 27?

Platform comparison

Market context

Polymarket currently has this contract at **0% YES**, so the market is pricing no meaningful chance that the London City Airport Station high on 27 July lands in the specified outcome range. For a trader, that is not a view on “hot or not” in the abstract; it is a claim about the exact **daily maximum temperature** recorded on the official Wunderground history page, settled in **USDC** via **conditional tokens** on **Polygon**.

The best frame of reference is London’s July climatology rather than a single headline forecast. London’s average July high is around **23°C**, but heatwaves can push daily peaks well into the low-to-mid 30s, and the Met Office has recently shown how quickly London can sit in a sustained hot spell before easing. That matters because a market like this often trades on whether the day’s maximum falls into a narrow band, not whether the city merely feels warm.

For catalysts, the key inputs are the intraday forecast path, any Met Office heat or thunderstorm warnings, and the timing of cloud cover or sea-breeze changes that can cap the maximum at London City Airport specifically. Traders will usually watch hour-by-hour updates rather than broad city forecasts, because the resolving source is a single station reading rather than a London-wide average. The market’s settlement window closes at 12:00 UTC, but the final high for the day can still be shaped by later meteorological developments before the Wunderground record is fixed.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Pronóstico: Highest temperature in London on July 27? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Polymarket Qué Es. 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 Qué Es 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.