Highest temperature in London on July 15?

Platform comparison

Market context

London City Airport is set to record its highest temperature for 15 July 2026, a single data point that will settle a conditional token market on Polygon. Today, Polymarket prices the contract with the frontrunner outcome at 28°C holding 57% of the implied probability, while 27°C sits at 22%, leaving the current 0% YES crowd-implied probability for the binary question effectively a misalignment with the multi-outcome distribution. Traders holding USDC on the chain can swap into these position tokens, betting on the precise Celsius range that will capture the day’s peak reading from the EGLC station.

Historical July peaks at London City Airport often cluster between 26°C and 30°C during warm spells, with 28°C a frequent median in recent years when southerly flows bring heat from continental Europe. The current 57% weighting on 28°C aligns with this pattern, suggesting the market views the 0% binary YES price as an outlier rather than a signal of imminent cold. Comparable cases from 2022 and 2023 show similar clustering, reinforcing that extreme deviations below 26°C are rare in mid-July under typical pressure patterns.

Traders should monitor the 12:00 UTC settlement deadline and the live Wunderground feed for EGLC, which updates hourly with the day’s maximum. The BBC Weather report for London City Airport today shows 13°C with falling pressure and southerly winds, a setup that could shift rapidly if a heat ridge develops overnight. No formal announcements are scheduled, but the dependency rests entirely on the Wunderground daily history page, where the final figure will be published and audited for resolution.

Sources: 1 · 2

Methodology

We track Highest temperature in London on July 15? 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

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.

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 PolyGram 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.