Highest temperature in London on August 4?

Platform comparison

Market context

The event is the highest **same-day temperature** recorded at London City Airport Station, measured in Celsius and settled from Wunderground’s daily history page, so a programmatic approach should watch the intraday maximum rather than the forecast headline alone. At 07:00 UTC, the live market is already pricing a warm day, with **28°C** the current frontrunner at **48%**, followed by **26°C**, **27°C** and **29°C** all at **19%** on Polymarket[4].

That shape is broadly consistent with August seasonality in London, where average highs sit in the low 20s °C and mid-to-high 20s are achievable on hotter spells[12][13]. Recent summer behaviour matters more than long-run averages: the Met Office said UK daily maximum temperatures have been running **2.1°C above average** this summer, while also noting that they have not been reaching record levels for the season so far[9]. London has already seen a 2026 high of **26.6°C** at Kew Gardens in April, which gives traders a practical anchor for how quickly the upper end can move when synoptic conditions favour heat[5][15].

For traders running bots or conditional orders, the key inputs are the day’s forecast evolution, any fresh heat-health messaging, and whether the London area stays under clear, slack conditions long enough to let the airport station print a late-afternoon peak[7][17]. The useful workflow is to compare forecast maxima from multiple providers with hourly updates, then trigger entries only if the implied range tightens around a specific bucket rather than broad “warm day” language; on a market settled to a single station reading, a one-degree shift can move the most likely outcome materially.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Bot UK, which mirrors the Polymarket order book directly.

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 Polymarket Bot UK. 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.

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 Bot UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.