Highest temperature in London on August 10?

Platform comparison

Market context

The contract will settle on the **highest Celsius temperature** recorded at London City Airport on 10 August, using Weather Underground’s Daily Observations rather than the headline Day High & Low figure. That distinction matters because traders are effectively pricing a single-station intraday peak, not a citywide average or a simplified summary, and the crowd is currently assigning **0%** to a yes-style outcome in the market framing while Polymarket’s live outcome pricing elsewhere shows the maximum clustered around the mid-20s Celsius rather than anything extreme.[1]

Historically, London’s August temperatures usually sit in the low-to-mid 20s Celsius, but the city has produced notable spikes when high pressure and warm air have aligned; the August record for the wider London area is far above normal summer levels, including **38.1°C at Kew Gardens** and **37.9°C at Heathrow** on 10 August 2003.[7][11] That matters for interpretation: a near-zero crowd reading is only sensible if the market is effectively asking whether London City Airport will top a much higher threshold, because forecast climatology for the date strongly favours the mid-20s and only occasional outsized heatwave scenarios push into the low 30s.[2][10][12]

The key catalysts are the short-range forecast updates for south-east England, any Heat Health Alert-style signalling, and the exact Weather Underground observation sequence through the settlement window, since late-day warming can still change the final maximum if the day turns sunnier or winds ease. Current comparator pricing on Polymarket shows **26°C and 27°C neck-and-neck at 43% each**, which is a much firmer consensus than the zero-implied reading you provided, while the broader forecast feed from AccuWeather points to a daily high around **27°C** for London, suggesting the main dispute is less about whether it will be warm and more about whether the market’s contract definition or strike structure makes the current odds appear misaligned.[1][2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on August 10? 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 Best Prediction Markets, which mirrors the Polymarket order book at 0% fees.

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

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 Best Prediction Markets. 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.

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.

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.