Highest temperature in London on July 16?

Platform comparison

Market context

London City Airport is currently recording 13°C with heavy humidity and falling pressure, a stark contrast to the scorching conditions required for the market’s high-temperature outcomes to trigger. The crowd-implied probability sits at 0% for any outcome above the lowest bracket, reflecting a consensus that today’s cool, damp air will cap the day’s peak well below historical mid-July extremes. This aligns with the immediate reality: southerly winds at 8 mph are pushing moisture rather than heat, making a breakthrough into the 20°C+ ranges highly improbable before the 12:00Z settlement window closes.

Historically, London City Airport rarely exceeds 25°C on 16 July unless a persistent heat dome from continental Europe locks in for days; the last such event occurred in 2022, when temperatures hit 31°C under a clear sky. In contrast, the past five years show a median peak of 19°C, with three of those years ending below 17°C due to Atlantic cloud cover. The current 0% pricing for higher ranges is therefore not contrarian but reflective of this damp baseline, though a sudden shift in wind direction could offer fleeting value if forecasters update models to show a rapid heat surge.

Traders should monitor the Met Office’s 18:00 UTC forecast update for any mention of a “heat advection” event or a sudden drop in cloud cover, as these are the only catalysts capable of reversing today’s trajectory. A recent BBC Weather analysis notes that falling pressure systems like the one currently over London typically suppress daytime highs by 3–5°C compared to stable anticyclones [2]. Without such a reversal, the market will likely resolve to the lowest bracket, leaving no value in betting against the 0% consensus.

Sources: 1 · 2

Methodology

We track Highest temperature in London on July 16? 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.

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 Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.