Highest temperature in London on June 21?

Platform comparison

Active sub-markets

Market context

London’s outcome depends on the single highest reading recorded at London City Airport Station during the day, so the market is really a test of the top end of the temperature distribution rather than the daytime average. The current 0% YES crowd price implies traders see the required threshold as effectively unreachable from the live setup, which is notable because London has already seen early-summer warmth elsewhere in the city this year, including 26.6C at Kew Gardens reported by Sky News. [2]

For context, comparable London heat events tend to move only when forecasts converge on an exceptional synoptic setup rather than ordinary June warmth. Bitget’s market page confirms the same London City Airport/Wunderground resolution source, while recent station-level data from 20 June shows a maximum of 25.8C at NW3 Weather, underscoring that the current market is asking for a fresh daily peak at a monitored airport site rather than a citywide headline temperature. [1][7]

From an access and compliance angle, this sort of market sits in a grey zone that matters for German and US users. Under Germany’s GlüStV framework, online betting and similar wagering activity can trigger licensing and geo-restriction issues, while in the US the CFTC’s reach can extend to event contracts that resemble derivatives. “No-KYC up to $1,500” generally means a platform may allow small-volume participation without full identity checks, but that does not remove location screening, withdrawal limits, or any regulatory restrictions that apply to this specific market.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 21? 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 Tax UK, 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 Tax UK 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 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Tax UK 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.