Highest temperature in London on August 10?

Platform comparison

Market context

London’s temperature is being priced as a **mildly warm** outcome rather than a true heatwave, with the market putting **27°C** in front at about **46%** and **26°C** close behind at roughly **43%**. That makes 27°C the favourite and 26°C the main underdog/value rival, while anything above that is a longer shot; in other words, consensus is clustered tightly around the upper 20s, not a blowout reading. The crowd is effectively saying the day should land in a narrow band, and the current 0% YES implied by the prompt would be wildly out of line with the live market picture.[1]

For framing, London’s August climate normally sits well below the sort of extremes that make the highest-temperature market easy to call, and the city’s record-type August readings show how rare it is to break far into the 30s. Historical highs for London on 10 August include 38.1°C at Kew Gardens and 37.9°C at Heathrow in 2003, but those are outliers rather than the base case.[5][12] Recent market pricing also points to the same shape: forecasts cited by Polymarket describe a peak near 27°C under mainly sunny skies after a hotter preceding day, which supports 27°C as the favourite and keeps 26°C as the more obvious contrarian angle if the day runs a touch cooler.[1]

The key trader watchpoint is the actual midday-to-afternoon evolution at London City Airport, because this market settles on the **highest recorded temperature** in Weather Underground’s Daily Observations table, not the summary high-low line.[14] That means late-afternoon warmth, brief cloud cover, or a modest forecast miss can matter more than the headline daily outlook, and revisions are still possible until the first datapoint for the next date appears.[1] Recent forecast products for London show a fairly broad August range, with daily highs varying widely across the month, so the real catalyst is whether local conditions on the day track the upper-20s expectation or ease back towards 26°C.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on August 10? 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 Who Will Win 2026. 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.

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.