Highest temperature in London on July 21?

Platform comparison

Market context

On 21 July 2026, the highest temperature recorded at London City Airport will determine which range this market settles into. The current crowd pricing shows 0% implied probability across all temperature bands, suggesting either thin liquidity or genuine uncertainty about which bracket will validate. Settlement depends on Wunderground's historical weather data for that specific station and date, with the resolution window closing at midday UTC on the day itself.

London's July temperatures have historically clustered between 20–26°C, though heat waves occasionally push readings above 28°C. The summer of 2022 saw London experience 40.3°C during an exceptional event, but such extremes remain statistical outliers. More typical July maxima at City Airport fall in the 22–25°C range. The 0% crowd probability across all bands likely reflects the market's early stage rather than confidence that no temperature will be recorded; traders should examine historical volatility patterns for mid-summer weather at this specific location to calibrate expectations.

The UK Met Office publishes extended forecasts roughly two weeks ahead, with greater precision arriving five to seven days before the target date. Climate patterns in late July 2026 will depend on Atlantic pressure systems and any continental heat advection—factors that become predictable only in the days immediately preceding settlement. Traders monitoring European weather models and seasonal outlooks from mid-July onwards will have the clearest signal for positioning. The settlement window's noon cutoff means morning temperatures could determine the outcome if the day peaks early.

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 Scam?, which mirrors the Polymarket order book directly.

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'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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Scam? trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.