Pronóstico: Highest temperature in London on August 20?

Platform comparison

Market context

On 20 August 2026, London City Airport's weather station will record a daily maximum temperature, and this market resolves to whichever Celsius range contains that figure. The contract currently trades at 0% implied probability across all temperature bands, suggesting either extreme confidence in a particular outcome or insufficient liquidity to establish meaningful pricing. Settlement hinges on Weather Underground's Daily Observations table rather than summary figures, a distinction that matters when automated systems occasionally diverge from granular station data. The USDC-denominated conditional tokens on Polygon will split according to whichever range captures the actual high, with resolution occurring at 12:00 UTC on the settlement date.

August temperatures in London have historically ranged from 17°C to 32°C over the past two decades, with the median daily maximum around 22–24°C. The 2022 heatwave pushed readings to 40°C, though such extremes remain statistical outliers. Recent summers have shown increasing volatility, with August 2023 delivering cooler-than-average conditions whilst 2024 saw above-normal warmth. These precedents suggest the market's current 0% reading across all bands reflects either a technical issue with contract initialisation or genuine uncertainty about which temperature bracket will dominate trader interest once the market matures.

The UK Met Office publishes extended forecasts roughly two weeks ahead, with meaningful accuracy emerging within seven days of the target date. Traders should monitor late-August 2026 weather pattern developments—Atlantic storm systems, continental high-pressure systems, and jet stream positioning all influence London's daily maxima. Any significant weather warnings or anomaly forecasts issued in early-to-mid August will likely trigger repricing across the temperature bands as conditional token holders adjust positions based on updated meteorological guidance.

Methodology

We track Pronóstico: Highest temperature in London on August 20? 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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 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.

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.