Highest temperature in London on August 1?

Platform comparison

Market context

London City Airport’s top temperature for 1 August is the underlying event, and the market is currently treating **26°C** as the favourite, with the crowd implying a **64%** chance that this is the winning band.[1] On that basis, the market is already pricing the favourite well ahead of the field, so the main value question is whether the consensus is too anchored to a single mid-20s outcome or whether the airport’s riverside location and the wider London urban heat island make a slightly hotter print more likely than the board suggests.[1]

History points to a fairly tight August distribution rather than a one-way outcome. Long-run London August averages sit in the low 20s, with monthly daytime highs commonly around **22°C** and the clearest skies often arriving early in the month, which is the sort of setup that can let temperatures overshoot forecasts if sunshine lasts through the afternoon.[2][4] For a handicapper, that keeps **25°C to 27°C** as the natural cluster around the favourite, while **24°C or below** looks like the more obvious underdog angle if cloud, breeze or a weaker-than-expected high keeps the maximum capped.

The key catalysts are the day’s actual sunshine, wind, and any late shift in the forecast model blend; for this market, the resolution source is the London City Airport Station record on Wunderground, so the final print depends on the station’s highest observed reading rather than a generic London forecast.[1] Traders should also watch whether nearby London stations report a hotter afternoon than City Airport, because coastal or river-influenced stations can lag the city centre by a degree or two even on broadly warm days. Recent UK reporting has already shown London capable of topping out in the mid-20s on summer hot spells, with 26.6°C recorded at Kew Gardens earlier in 2026, so the contrarian case is not for an extreme number, but for a modest beat over the current 26°C consensus.[3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

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 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 Who Will Win 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.