Highest temperature in London on June 30?

Platform comparison

Market context

The highest temperature recorded at London City Airport on 30 June 2026 will determine the outcome of this prediction market, with the current crowd-implied probability of a "YES" resolution sitting at 0%. On Polymarket, this contract is priced in USDC on the Polygon network, where conditional tokens reflect the market’s belief that the temperature will fall outside the specific range being wagered on. The settlement window closes at 12:00 UTC on 30 June 2026, once Wunderground publishes the first data point for that date.

Historical data frames this 0% probability as a rational assessment rather than an outlier. In June 2026, Kew Gardens in southwest London recorded 26.6°C, marking the hottest day of the year so far according to the Met Office[4]. Meanwhile, London City Airport saw a maximum of 24.6°C on 29 June, with forecasts predicting a similar high of 24°C for 30 June[7][9]. These figures suggest the temperature will likely remain in the lower 20s, well below the thresholds that would trigger a "YES" outcome for higher ranges.

Traders should monitor the Met Office’s daily forecast updates and Wunderground’s real-time data releases for any sudden shifts in temperature patterns. The Met Office has already confirmed that sunny intervals and mild temperatures are expected to persist into 1 July, reinforcing the current market stance[6][9]. Any unexpected heatwave announcements or changes in the scheduled weather warnings would be the primary catalysts to watch, though current data indicates no immediate deviation from the mild trend.

Sources: 1 · 2 · 3 · 4 · 5

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

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 Polymarket Scam? trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.