Highest temperature in London on June 23?

Platform comparison

Active sub-markets

Market context

The underlying real-world event is the peak temperature recorded at London City Airport on 23 June 2026, with the crowd currently assigning a 100% probability to the outcome being "32°C or below". On Polymarket, this contract trades on the Polygon network using USDC, where conditional tokens reflect the market’s absolute certainty in a cool day despite the date being today. The volume sits at $70.1K, with the next most liquid outcomes being 34°C ($35.5K) and 35°C ($28K), yet the "YES" side for the lower range dominates the liquidity pool entirely.

Historical patterns for late June in London suggest that temperatures rarely breach 32°C unless a strong heatwave from continental Europe arrives, a scenario not currently forecast. Comparable markets, such as the NYC event on the same date, show a 66% probability for 70–71°F (roughly 21°C), reinforcing the likelihood of moderate conditions in the UK. Even during the recent heat spike where Heathrow reached 37.8°C, London City Airport typically records lower figures due to its coastal proximity and urban cooling effects, making the current 100% probability for the lower range statistically grounded.

Traders should monitor the Met Office’s 7-day forecast updates and any sudden shifts in southerly wind pressure, which could signal an incoming warm front. The resolution source, Wunderground, will only publish data once the first datapoint for the following date is available, meaning any revisions to temperatures are locked after that timestamp. While no immediate announcements suggest a heatwave, the falling pressure reading of 1012mb noted in current observations indicates unstable conditions that could bring rain rather than heat, further supporting the market’s current pricing.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 23? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

Where can I trade this market with the lowest fees?

On Polymarket Scam?, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket Scam? is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Scam? triggers a quick verification flow that finishes in minutes.

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.