Pronóstico: Highest temperature in London on August 4?

Platform comparison

Market context

Polymarket is currently pricing the London City Airport reading for 4 August as a tight, low-variance summer temperature event, with the leading contract at **28°C** on **48%** and several nearby outcomes clustered behind it. For a trader holding USDC on Polygon, that means the market is mostly debating whether the day’s peak lands in the high-20s or slips back towards the mid-20s, rather than whether London reaches an extreme heat outcome. Shares in the correct temperature band settle to **$1** if that band wins, via the market’s conditional-token mechanics.

That shape is consistent with London’s August profile, where the city typically sits in the high teens and only occasionally pushes into the upper 20s or low 30s. Recent UK weather coverage has also shown how quickly southeast England can heat up during a settled spell: the Met Office and later reporting described London-area temperatures reaching **26.6°C** at Kew Gardens and, in another hot spell, around **35°C** in parts of the south-east, underscoring how a few degrees of synoptic change can move the winning band materially. The August record for the UK sits far above normal summer levels, but that is not the base case for most London days.[15][17][18]

For traders, the key catalysts are the next London forecast updates, whether high pressure builds over southern England, and the actual hourly progression at London City Airport before the **12:00 UTC** cutoff. Because the market resolves from Wunderground’s daily history page for that station, the relevant question is not just the daytime maximum in abstract, but when the strongest warming occurs and whether cloud, showers, or wind keep the station below the current favourite band. The contract remains open until the first data point for the day is published on the resolution source, so late-morning model shifts and live airport observations are the main inputs into price discovery.[3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Pronóstico: Highest temperature in London on August 4? 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 Qué Es, 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 Polymarket Qué Es. 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 fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

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.