Highest temperature in London on July 13?

Platform comparison

Market context

The market hinges on whether London City Airport records a temperature above the implied threshold on 13 July 2026, with current pricing suggesting only a 6% chance of a “YES” outcome. Today’s forecast shows a high of 27°C at the station, well below extreme heat levels, and the settlement window closes at 12:00 UTC, meaning only the first half of the day counts for resolution.

Historically, July is London’s hottest month, averaging 22°C highs at London City Airport, though record-breaking heatwaves have pushed temperatures significantly higher in recent years. The UK’s all-time record of 40.2°C was set in July 2022 at Heathrow, but London City Airport typically records slightly lower peaks due to its urban riverine location and smaller exposure to continental airflows [1][5]. A 6% probability aligns with the rarity of extreme highs at this specific site, especially when today’s conditions are moderate and no major heatwave is forecast.

Traders should monitor real-time updates from Wunderground and the Met Office for any sudden shifts in temperature before 12:00 UTC, as the market resolves on the highest reading recorded up to that point. With today’s high already observed near 27°C and no announcements of extreme heat, the catalyst for a spike would require an unforecasted surge in southerly winds or a rapid pressure drop—both unlikely given current stable conditions [3][6]. Programmatically, bots should poll Wunderground’s hourly archive every 15 minutes and trigger conditional orders only if the live reading breaches the threshold by more than 2°C above the current high.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on July 13? 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Polymarket Bot UK 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.