Highest temperature in London on June 25?

Platform comparison

Active sub-markets

Market context

The underlying event is the peak heat recorded at London City Airport on 25 June 2026, measured in degrees Celsius by Wunderground. This single data point will determine the market outcome, with the current crowd-implied probability of 0% suggesting traders believe a specific temperature range is virtually impossible to hit.

Historical patterns frame this low probability; recent June days in London have seen highs near 30C, with Kew Gardens recording 26.6C as the hottest day of 2026 so far[3], while London City Airport hit 33.9C on 23 June 2026[5]. These comparable cases indicate that temperatures in the mid-30s are plausible, making the 0% signal for a specific range appear inconsistent with recent volatility.

Traders should monitor the Met Office forecast for bank holiday Monday, which predicts climbs to 30C, and watch for any sudden shifts in the high-pressure system over the UK[8]. Regulatory accessibility remains a key factor; German GlüStV implications and US CFTC reach define the legal landscape, while the 'no-KYC up to $1,500' threshold allows immediate participation for smaller accounts without identity verification, directly impacting liquidity for this weather-specific market.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 25? 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

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.

What does it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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, PolyGram 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.