Highest temperature in London on July 6?

Platform comparison

Market context

London is currently surging into heatwave territory as temperatures climb sharply through the early hours of 6 July, with forecasts indicating a significant burst of summer heat that could push peak readings well above 30°C by midday. This rapid escalation in the last 24 hours has overturned the previous 0% crowd-implied probability for the upper temperature bands, driven by a distinct shift in atmospheric pressure that is locking in long periods of sunshine and very warm afternoons across the capital.

Historical data frames this sudden spike as an outlier rather than a routine occurrence, given that London’s average July high sits at 27°C, yet the record peak of 40.2°C recorded in 2022 demonstrates the city’s capacity for extreme volatility during stable high-pressure systems. While the 32% probability assigned to the 30°C band suggests traders are cautious, the current trajectory mirrors the intense heat build-up seen in mid-July 2022, where temperatures climbed relentlessly before peaking, making the current 0% floor for higher bands increasingly fragile against the backdrop of these comparable extreme events.

Traders must monitor the immediate development of isolated thunderstorms, which could interrupt the heat build-up if convection triggers as the heat intensifies, alongside real-time updates from NWP model revisions that are expected to reprice this contract rapidly. A recent forecast from a weather video update highlights a small risk of storms as humidity rises, meaning the market’s resolution hinges on whether dry conditions dominate or if early morning showers on Sunday disrupt the heatwave before the settlement window closes at noon.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on July 6? 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'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 Prediction Today trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.